Method for syngas clean-up of semi-volatile organic compounds

ABSTRACT

A system and method for processing unconditioned syngas first removes solids and semi-volatile organic compounds (SVOC), then removes volatile organic compounds (VOC), and then removes at least one sulfur containing compound from the syngas. Additional processing may be performed depending on such factors as the source of syngas being processed, the products, byproducts and intermediate products desired to be formed, captured or recycled and environmental considerations.

RELATED APPLICATIONS

This is a Divisional of U.S. patent application Ser. No. 14/347,431filed Mar. 26, 2014, now U.S. Pat. No. 9,499,404, which is a 371 USNational Phase of PCT/US2012/057594, filed Sep. 27, 2012, which, inturn, claims priority to U.S. Provisional Patent Application No.61/539,924 filed Sep. 27, 2011. The contents of the aforementionedapplications are incorporated by reference in their entirety.

FIELD OF THE INVENTION

The present invention is directed to the processing of syngas createdfrom the processing of carbonaceous material.

BACKGROUND

A raw synthesis gas product, hereinafter called ‘unconditioned syngas’,is generated by the process of steam reforming, and may be characterizedby a dirty mixture of gases and solids, comprised of carbon monoxide,hydrogen, carbon dioxide, methane, ethylene, ethane, acetylene, and amixture of unreacted carbon and ash, commonly called ‘char’, as well aselutriated bed material particulates, and other trace contaminants,including but not limited to ammonia, hydrogen chloride, hydrogencyanide, hydrogen sulfide, carbonyl sulfide, and trace metals. FIG. 28presents a more complete list of components that may be found inunconditioned syngas.

Unconditioned syngas may also contain a variety of volatile organiccompounds (VOC) or aromatics including benzene, toluene, phenol,styrene, xylene, and cresol, as well as semi-volatile organic compounds(SVOC) or polyaromatics, such as indene, indan, napthalene,methylnapthalene, acenapthylene, acenapthalene, anthracene,phenanthrene, (methyl-) anthracenes/phenanthrenes, pyrene/fluoranthene,methylpyrenes/benzofluorenes, chrysene, benz[a]anthracene,methylchrysenes, methylbenz[a]anthracenes, perylene, benzo[a]pyrene,dibenz[a,kl]anthracene, and dibenz[a,h]anthracene.

Syngas processing technology applications can generally be defined asindustrial processing systems that accept a syngas source and produce orsynthesize something from it. Normally, these can be categorized intosystems that generate hydrogen, ethanol, mixed alcohols, methanol,dimethyl ether, chemicals or chemical intermediates (plastics, solvents,adhesives, fatty acids, acetic acid, carbon black, olefins,oxochemicals, ammonia, etc.), Fischer-Tropsch products (LPG, Naptha,Kerosene/diesel, lubricants, waxes), synthetic natural gas, or power(heat or electricity).

A plethora of syngas processing technologies exist, each convertingsyngas into something, and each possessing its own unique synthesis gascleanliness requirement. For example, a Fischer-Tropsch (FT) catalyticsynthesis processing technology requires more stringent cleanlinessrequirements when compared to a methanol synthesis application. This isbecause some FT cobalt catalysts are extremely sensitive to sulfur,resulting in deactivation, whereas sulfur does not pose a problem forsome catalytic methanol applications. Therefore, a vast array ofpermutations or combinations of syngas clean-up operational sequencesteps are possible to meet the economical and process intensive demandsof synthesis gas conversion technologies.

SUMMARY OF THE INVENTION

In one aspect, the present invention is directed to a method ofprocessing unconditioned syngas. The method comprises removing solidsand semi-volatile organic compounds (SVOC) from the unconditionedsyngas, then removing volatile organic compounds (VOC), and thenremoving at least one sulfur containing compound.

In another aspect, the present invention is directed to a system forprocessing unconditioned syngas. The system comprises means for removingsolids and semi-volatile organic compounds (SVOC) from the unconditionedsyngas, a compressor configured to receive and compress the resultantsyngas stream, means for removing volatile organic compounds (VOC) fromthe compressed resultant syngas stream, and at least one bed configuredto receive VOC-depleted syngas stream and remove at least one sulfurcompound.

In yet another aspect, the present invention is directed to a method forremoving solids and semi-volatile organic compounds (SVOC) fromunconditioned syngas. The method includes (a) contacting theunconditioned syngas with a solvent and water to thereby form anintermediate SVOC-depleted syngas containing steam, and a first mixturecomprising SVOC, solids, solvent and water; (b) removing steam from theintermediate SVOC-depleted syngas containing steam to form: (i) a firstdepleted syngas stream which has a reduced amount of SVOC relative tothe unconditioned gas stream, and (ii) a second mixture comprising SVOC,solids, solvent and water; (c) separating the water within the secondmixture based upon immiscibility so that the SVOC, solids and solventcollect together to form a third mixture above the water; (d) separatingthe solids from the SVOC and solvent in a vessel having at least oneliquid phase candle filter such that the solids agglomerate on a surfaceof the candle filter and form a filter cake having density greater thanthat of water within the vessel; (e) backflushing the candle filter toloosen the filter cake so that the filter cake sinks into the waterwithin the vessel; and (f) removing the filter cake from a bottom of thevessel.

In still another aspect, the present invention is directed to a systemfor removing solids and semi-volatile organic compounds (SVOC) fromunconditioned syngas. The system includes: a venturi scrubber configuredto receive the unconditioned syngas, solvent and water and output anintermediate SVOC-depleted syngas containing steam together with a firstmixture comprising SVOC, solids, solvent and water; a char scrubberconfigured to receive the intermediate SVOC-depleted syngas containingsteam and the first mixture, and separately output: (i) a first depletedsyngas stream which has a reduced amount of SVOC relative to theunconditioned gas stream, and (ii) a second mixture comprising SVOC,solids, solvent and water; a decanter configured to receive the secondmixture and separate the water within the second mixture based uponimmiscibility so that the SVOC, solids and solvent collect together toform a third mixture above the water within the decanter, the decanterfurther configured to separately output the water and the third mixture;and a vessel arranged to receive the third mixture, the vessel having atleast one liquid phase candle filter and a vessel bottom provided with adrain port; wherein: the candle filter is capable of operating so that:(i) the solids agglomerate on a surface of the candle filter and form afilter cake, and (ii) the SVOC and solvent are removed through thecandle filter, and the drain port is suitable for removing filter caketherethrough.

The present invention is further directed to a system for processingunconditioned syngas which include the aforementioned system forremoving solids and semi-volatile organic compounds (SVOC), incombination with various types of VOC-removal equipment andsulfur-removal equipment which operate under pressure.

These and other aspects of the present invention are described below infurther detail.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1—Syngas Clean-Up Step Flow Diagram

FIG. 1A-1D—Syngas Clean-Up System

FIGS. 1E-1F—Abbreviated Syngas Clean Up System and Process

FIG. 2—Step B, Hydrocarbon Reforming Module

FIG. 3—Step C, Syngas Cooling Module

FIG. 4—Step D, Option 1, Block Process Flow Diagram for Solids & SVOCRemoval

FIG. 5—Step D, Solids & SVOC Removal Module

FIG. 6—Step D, Option 1, Continuous Solvent Filtration & FiltrateBackflush Regeneration Module

FIG. 7—Filtrate Backflush Regeneration Operation Process Flow Diagram

FIG. 8—Step D, Option 1, Sequence Step Operation Flow Diagram

FIG. 9—Step D, Option 2, Block Process Flow Diagram for Solids & SVOCRemoval

FIG. 10—Step D, Option 2, Sequence Step Operation Process Flow Diagram

FIG. 11—SVOC Separation System, Option 1, SVOC Flash Separation Module

FIG. 12—SVOC Separation System, Option 2, SVOC Sorptive SeparationModule

FIG. 13—Step E, Chlorine Removal Module

FIG. 14—Step F, Sulfur Removal Module

FIG. 15—Step G, Particulate Filtration Module

FIG. 16—Step H, Syngas Compression Module

FIG. 17—Step I, VOC Removal Module

FIG. 18—Step I, VOC Separation System, Option 1, TSA/PSA System

FIG. 19—Step I, VOC Separation System, Option 2, Fluidized Bed AdsorberSystem

FIG. 20—Step J, Metal Removal Module

FIG. 21—Step K, Ammonia Removal Module

FIG. 22—Step L, Ammonia Polishing Module

FIG. 23—Step M, Heat Addition Module

FIG. 24—Step N, Carbonyl Sulfide Removal Module

FIG. 25—Step O, Sulfur Polishing Module

FIG. 26—Step P, Carbon Dioxide Removal Module

FIG. 27—Steps Q, R, & S Heat Integration & Hydrocarbon Reforming Module

FIG. 28—Typical Components within Unconditioned Syngas

FIG. 29—Sequence Step Parameter & Contaminant Removal Efficiency

FIGS. 30A-30F—List of Combinations of Steps Associated With VariousSyngas Clean-Up Methods

DETAILED DESCRIPTION

FIG. 1 lists each syngas clean-up operational sequence step that may beincluded in an overall syngas cleaning process. As discussed below, notall steps need be performed in every implementation and so one or moreof the steps may be optional.

The focus of the following text is to describe in detail thefunctionality, flexibility, and variability of each syngas clean-upprocess operational sequence step in communication with one another. Itis further an object of the following text to elaborate upon the varyingpermutations of syngas clean-up process operational sequence steps toform an integrated syngas clean-up process.

Selection of a precise combination and/or permutation of steps andequipment may be important, as dictated by various criteria. Dependingupon the process conditions involved, albeit be chemical and reactionaryin nature, temperature, pressure, or presence or absence of a specificcontaminate or component species, (such as water, for example) certainlogical requirements and practical proprietary heuristics dictate wherein the entire permutable sequence of unit operations a specific syngasclean-up operational sequence step may be placed.

A multitude of permutations of syngas operational sequence steps arepossible to realize an overall integrated syngas clean-up process.Syngas contaminant tolerances, or cleanliness requirements of downstreamsyngas processing technologies, dictate how elaborate a given integratedsyngas clean-up process must be.

The idea of a control volume is an extremely general concept used widelyin the study and practice of chemical engineering. Control volumes maybe used in applications that analyze physical systems by utilization ofthe laws of conservation of mass and energy. They may be employed duringthe analysis of input and output data of an arbitrary space, or region,usually being a chemical process, or a portion of a chemical process.They may be used to define process streams entering a single piece ofchemical equipment that performs a certain task, or they may be used todefine process streams entering a collection of equipment, and assetswhich work together to perform a certain task.

With respect to the surrounding text, a control volume is meaningful interms of defining the boundaries of a particular syngas clean-upsequence step. With respect to the accompanied text, a sequence step maybe defined as a member of an ordered list of events. These events may bearranged in a plethora of varying ways depending upon any number ofrequirements dictated by contaminant tolerances of any type of syngasprocessing technology. Each sequence step is assigned a namecorresponding to the problem is solves.

The arrangements of equipment contained within each control volume arethe preferred ways of accomplishing each sequence step. Furthermore, allpreferred embodiments are non-limiting in that any number ofcombinations of unit operations, equipment and assets, includingpumping, piping, and instrumentation, may be used as an alternate.However, it has been our realization that the preferred embodiments thatmake up each sequence step are those which work best to realizecontaminant removal efficiencies as described in FIG. 29. Nonetheless,any types of unit operations or processes may be used within any controlvolume shown as long as it accomplishes the goal of that particularsequence step.

FIGS. 1A through 1D depict one embodiment of a system consistent withthe steps shown in FIG. 1 to realize an overall integrated syngasclean-up process. The specific details of each control volume areelaborated upon in the accompanied text below.

FIG. 1A illustrates a Hydrocarbon Reforming Control Volume [B-1]accepting an unconditioned syngas through a Sequence Step B Syngas Inlet[B-IN] and outputting a syngas of improved quality through a SequenceStep B Syngas Discharge [B-OUT]. Syngas quality improvement is definedbelow and is achieved through hydrocarbon reforming and/or cracking withthe use of either partial oxidative, catalytic, or non-thermalnon-catalytic systems or processes.

Syngas of improved quality is then routed to a Syngas Cooling ControlVolume [C-1] through a Sequence Step C Syngas Inlet [C-IN] which reducesthe temperature of the syngas prior to outputting the cooled syngasthrough a Sequence Step C Syngas Discharge [C-OUT]. Any number ofprocesses and unit operations may be employed to cool the syngas withinthis control volume and the objective of this process step is to reducethe temperature of the syngas prior to the removal of solids andsemi-volatile organic compounds (SVOC) within the following sequencestep.

Solids and SVOC are next removed from the unconditioned syngas within aSolids Removal & SVOC Removal Control Volume [D-1]. A solids and SVOCladen Sequence Step D Syngas Inlet [D-IN] is provided to the controlvolume where the assets included therein remove solids and SVOC from thesyngas to output a solids and SVOC-depleted Sequence Step D SyngasDischarge [D-OUT]. It is preferable to remove solids and SVOC utilizingthe systems and methods as described below, however any type of systemsand methods may be utilized within this control volume to accomplish thegoal of the sequence step to remove solids and SVOC from syngas.

FIG. 1B illustrates the solids and SVOC-depleted Sequence Step D SyngasDischarge [D-OUT] being routed to a Chlorine Removal Control Volume[E-1] which accepts through a chlorine laden Sequence Step E SyngasInlet [E-IN] and outputs a chlorine depleted Sequence Step E SyngasDischarge [E-OUT]. It is preferable that chlorine is scrubbed from thesyngas with the use of water, however any type of scrubbing liquid maybe used, and in addition, any type of chlorine removal process or systemmay be employed to accomplish the goal of the sequence step to removechlorine from syngas.

Syngas depleted of chlorine is then routed to a Sulfur Removal ControlVolume [F-1] which accepts as a sulfur laden Sequence Step F SyngasInlet [F-IN], and outputs a sulfur-depleted Sequence Step F SyngasDischarge [F-OUT]. It is preferable that sulfur is scrubbed from thesyngas with the use of a triazine hydrogen sulfide scavenger, howeverany type of scrubbing liquid may be used, and in addition, any type ofsulfur removal process or system may be employed to accomplish the goalof the sequence step to remove sulfur from syngas.

Syngas depleted of sulfur is then routed to a Particulate FiltrationControl Volume [G-1] which accepts as a particulate laden Sequence StepG Syngas Inlet [G-IN], and outputting a particulate depleted SequenceStep G Syngas Discharge [G-OUT]. It is desirable to have this sequencestep in place immediately prior to the compression step so as to providea final separation of any solids that may carry over, or becomeelutriated, during any intermittent operational upset within theupstream solids removal unit operations.

Syngas is then routed to a Syngas Compression [H] step wherein a SyngasCompressor accepts as a Sequence Step H Syngas Inlet [H-IN], and outputsa Sequence Step H Syngas Discharge [H-OUT]. The following describedsequence steps and processes illustrated in FIGS. 1C through 1Dprimarily operate at a pressure higher than the preceding describedsequence steps, relatively, since the compressor elevates the pressureof the syngas so that the outlet syngas is at a higher pressure inrelation to the inlet syngas pressure.

As seen in FIG. 1C, compressed syngas is then routed to a VolatileOrganic Compounds (VOC) Removal Control Volume [I-1], which accepts as aVOC laden Sequence Step I Syngas Inlet [I-IN], and outputs aVOC-depleted Sequence Step I Syngas Discharge [I-OUT]. It is preferablethat VOC is removed with the use of pressure swing and temperature swingadsorption and desorption methods and systems utilizing eithermicrochannel heat exchangers, or pressure or temperature swingadsorption and desorption methods and systems utilizing fixed beds, oreven utilizing fluidized bed systems and methods in which syngasfluidizes a sorbent material to remove VOC within the syngas, and inaddition, any type of VOC removal process or system may be employed toaccomplish the goal of the sequence step to remove VOC from syngas.

VOC-depleted syngas is the routed to a Metal Removal Control Volume[J-1] which accepts through a metal laden Sequence Step J Syngas Inlet[J-IN], and outputs a metal depleted Sequence Step J Syngas Discharge[J-OUT]. It is preferable that metals are adsorbed from the syngas withthe use fixed bed systems and methods utilizing suitable adsorbentmaterials, however absorption may employed instead, and in addition, anytype of metals removal process or system may be employed to accomplishthe goal of the sequence step to remove metal from syngas.

Syngas depleted of metals is then routed to an Ammonia Removal ControlVolume [K-1] which accepts as an ammonia laden Sequence Step K SyngasInlet [K-IN], and outputs an ammonia-depleted Sequence Step K SyngasDischarge [K-OUT]. It is preferable that ammonia is scrubbed from thesyngas with the use of water, however any type of scrubbing liquid maybe used, and in addition any type of ammonia removal system may beemployed to accomplish the goal of the sequence step to remove ammoniafrom syngas.

Syngas depleted of ammonia is then routed to an Ammonia PolishingControl Volume [L-1] which accepts as a Sequence Step L Syngas Inlet[L-IN], and outputs Sequence Step L Syngas Discharge [L-OUT]. It ispreferable that ammonia is polished from the syngas using fixed bedadsorption systems and methods; however any type of ammonia polishingsystem may be employed to accomplish the goal of the sequence step topolish ammonia from syngas.

FIG. 1D displays a series of sequence steps to be performed to removesulfur containing compounds. Syngas polished of ammonia is routed to aHeat Addition Control Volume [M-1], which accepts through a SequenceStep M Syngas Inlet [M-IN], and outputs a Sequence Step M SyngasDischarge [M-OUT]. The goal of this control volume is to elevate thetemperature of the syngas prior to removal of sulfur containingcompounds.

Syngas at an elevated temperature is then routed to a Carbonyl SulfideRemoval Control Volume [N-1] which accepts a carbonyl sulfide ladenSequence Step N Syngas Inlet [N-IN], and outputs a sulfur-depletedSequence Step N Syngas Discharge [N-OUT]. It is preferred to accomplishthe goals of this sequence step with the utilization of a packed bed ofan alumina based material which allows for the hydrolysis of carbonylsulfide into carbon dioxide and hydrogen sulfide, however any type ofcarbonyl sulfide removal system or method, such as adsorption orabsorption type systems, may be employed to accomplish the goal of thesequence step to remove carbonyl sulfide from syngas.

Sulfur-depleted syngas is then routed to a final Sulfur PolishingControl Volume [O-1] which accepts as a Sequence Step O Syngas Inlet[O-IN], and outputs through a Sequence Step O Syngas Discharge [O-OUT].It is preferable that sulfur is polished from the syngas using fixed bedadsorption systems and methods; however any type of sulfur polishingsystem may be employed to accomplish the goal of the sequence step topolish sulfur from syngas.

Sulfur-depleted syngas is then routed to a Carbon Dioxide RemovalControl Volume [P-1], which accepts through a carbon dioxide ladenSequence Step P Syngas Inlet [P-IN], and outputting a carbon dioxidedepleted Sequence Step P Syngas Discharge [P-OUT]. Membrane basedprocesses are the preferred system utilized to remove carbon dioxidefrom syngas, however other alternate systems and methods may be utilizedto accomplish the goals of this sequence step, not limited to adsorptionor absorption based carbon dioxide removal systems and processes. In afurther embodiment, carbon dioxide may be reduced within this sequencestep by use of a carbon dioxide electrolyzer.

FIG. 1E represents a preferred embodiment where an unconditioned syngasis provided to a Solids Removal & SVOC Removal Control Volume [D-1]which accepts unconditioned syngas through a solids and SVOC ladenSequence Step D Syngas Inlet [D-IN] and removes solids and SVOC from theunconditioned syngas to form a first depleted syngas stream therebydischarging through a solids and SVOC-depleted Sequence Step D SyngasDischarge [D-OUT]. The first depleted syngas stream has a reduced amountof solids and SVOC relative to the unconditioned syngas.

The first depleted syngas stream is then routed to a Volatile OrganicCompounds (VOC) Removal Control Volume [I-1], which accepts as a VOCladen Sequence Step I Syngas Inlet [I-IN], and removes volatile organiccompounds (VOC) from the first depleted syngas stream to form a seconddepleted syngas stream which has a reduced amount of VOC relative to thefirst depleted syngas stream thereby outputting through a VOC-depletedSequence Step I Syngas Discharge [I-OUT].

The second depleted syngas stream is then routed to a Carbonyl SulfideRemoval Control Volume [N-1] which accepts as a carbonyl sulfide ladenSequence Step N Syngas Inlet [N-IN], and removes at least one sulfurcontaining compound from the second depleted syngas stream to produce asulfur-depleted syngas stream which has a reduced sulfur amount ofsulfur relative to the second depleted syngas stream thereby outputtingas a sulfur-depleted Sequence Step N Syngas Discharge [N-OUT].

The sulfur-depleted syngas stream is then routed to a final SulfurPolishing Control Volume [O-1] which accepts as a Sequence Step O SyngasInlet [O-IN], and provides an additional sulfur polishing step to reducetotal sulfur content to less than 100 part-per billion therebydischarging through a Sequence Step O Syngas Discharge [O-OUT].

FIG. 1F represents a preferred embodiment where an unconditioned syngasis provided to a Solids Removal & SVOC Removal Control Volume [D-1]which accepts unconditioned syngas through a solids and SVOC ladenSequence Step D Syngas Inlet [D-IN] and removes solids and SVOC from theunconditioned syngas to form a first depleted syngas stream therebydischarging through a solids and SVOC-depleted Sequence Step D SyngasDischarge [D-OUT]. The first depleted syngas stream has a reduced amountof solids and SVOC relative to the unconditioned syngas.

The first depleted syngas stream is then routed to a Volatile OrganicCompounds (VOC) Removal Control Volume [I-1], which accepts as a VOCladen Sequence Step I Syngas Inlet [I-IN], and removes volatile organiccompounds (VOC) from the first depleted syngas stream to form a seconddepleted syngas stream which has a reduced amount of VOC relative to thefirst depleted syngas stream thereby outputting through a VOC-depletedSequence Step I Syngas Discharge [I-OUT].

The second depleted syngas stream is then routed to a final SulfurPolishing Control Volume [O-1] which accepts as a Sequence Step O SyngasInlet [O-IN], and provides an additional sulfur polishing step togenerate a sulfur-depleted syngas stream which has a reduced sulfuramount of sulfur relative to the second depleted syngas stream therebydischarging through a Sequence Step O Syngas Discharge [O-OUT].

Sequence Step B, Hydrocarbon Reforming [B]

FIG. 2 illustrates Sequence Step B, Hydrocarbon Reforming [B].Hydrocarbon Reforming Control Volume [B-1] encapsulates the preferredarrangement of equipment and assets that work together to provide amethod for improving syngas quality by reforming and/or cracking one ormore undesirable syngas constituents into desirable syngas constituents.

As used herein the term “desirable syngas constituents” or “favorablesyngas constituents” or variants thereof refer to hydrogen (H₂) andcarbon monoxide (CO).

As used herein the term “undesirable syngas constituents” refer to anyconstituents present in syngas other than hydrogen (H₂) and carbonmonoxide (CO), including, but not limited to, carbon dioxide (CO₂),hydrocarbons, VOC, SVOC, nitrogen containing compounds, sulfurcontaining compounds, as well as other impurities that are present inthe feedstock that can form during thermochemical syngas generationprocesses.

As used herein the term “hydrocarbon” refers to organic compounds ofhydrogen and carbon, CxHy. These may include, but not limited to methane(CH₄), ethane (C₂H₆), ethylene (C₂H₄), propane (C₃H₈), benzene (C₆H₆),etc. Hydrocarbons include VOC and SVOC.

As used herein “improved syngas quality” or variants thereof refer to asyngas where at least one undesirable syngas constituent is reformedand/or cracked into at least one desirable syngas constituent.

As used herein the term “cracking” or “cracked” or variations thereofmean that undesirable syngas constituents, including hydrocarbons, SVOC,and/or VOC, are reacted with a suitable catalyst and/or in a partialoxidative environment and/or in a non-thermal non-catalytic plasmaenvironment, to provide chemical species comprised of decreasedmolecular weights. For example, raw syngas that may contain propane(C₃H₈), having a molecular weight of 44 lb/mol, may be cracked intocompounds comprised of lesser molecular weights, for example, methane(CH₄) and ethylene (C₂H₄), both having lesser molecular weights thanthat of propane, being 16 lb/mol and 28 lb/mol, respectively.

As used herein the term “reforming” or “reformation” or variationsthereof mean that undesirable syngas constituents, includinghydrocarbons, SVOC, and/or VOC, are converted into desirable syngasconstituents. For example, in the presence of an oxidant and a suitablecatalyst and/or in a partial oxidative environment and/or in anon-thermal non-catalytic plasma environment, methane (CH₄) can bereformed into carbon monoxide (CO) and hydrogen (H₂).

Unconditioned syngas may be transferred from a Syngas Generation [A]system, preferably a biomass steam reforming system (not shown), androuted through Sequence Step B Syngas Inlet [B-IN] into a HydrocarbonReforming Control Volume [B-1], which produces a Sequence Step B SyngasDischarge [B-OUT].

This Hydrocarbon Reformer [8000] is preferably of a non-thermal,non-catalytic, cold plasma gliding-arc type, however, partial oxidation,and/or catalytic systems, or combinations thereof, may be employed toaccomplish the sequence step objective of hydrocarbon reforming and/orcracking for syngas quality improvement. The Hydrocarbon Reformergenerates a syngas or improved quality and depleted of VOC, SVOC, andother less desirable constituents, including, carbon dioxide, methane,ethylene, ethane, and acetylene, which may then be routed from thereformer through a Sequence Step B Syngas Discharge [B-OUT].

Additives [2], including solids possessing low ionization potential, notonly including alkali metals, preferably sodium compounds or potassiumcompounds or mixtures thereof, may be provided to the HydrocarbonReformer. Utilization of these additives serves the purpose to increasethe ionization energy in the cold plasma reaction zone within theHydrocarbon Reformer, and thus aiding the decomposition of SVOC, andVOC, along with the less desirable syngas constituents, into favorableconstituents including carbon monoxide and hydrogen. The presence of theadditives within the Hydrocarbon Reformer favorably alters the electrondensity within the cold plasma arc reaction zone. This in turn enhancesthe thermochemical and electrochemical properties within the plasmareaction zone resultantly increasing the efficiency of the HydrocarbonReformer to reform and/or crack the VOC, SVOC, and other less desirableconstituents into carbon monoxide and hydrogen.

An oxidant source [4], including, but not limited to, carbon dioxide,steam, air, or oxygen, may be made available to the Hydrocarbon Reformerto increase the reforming and/or cracking efficiency to promoteproduction of carbon monoxide and hydrogen.

A gaseous hydrocarbon source [6] may be made available to theHydrocarbon Reformer and may include, natural gas, syngas, refineryoffgases, methanol, ethanol, petroleum, methane, ethane, propane,butane, hexane, benzene, toluene, xylene, or even waxes or low meltingsolids such as paraffin wax and naphthalene.

Sequence Step C, Syngas Cooling [C]

FIG. 3 illustrates Sequence Step C, Syngas Cooling [C], wherein SyngasCooling Control Volume [C-1] accepts a Sequence Step C Syngas Inlet[C-IN] and outputs a Sequence Step C Syngas Discharge [C-OUT].

Syngas may be routed through a Sequence Step C Syngas Inlet [C-IN], to aHeat Recovery Steam Generator (HRSG) Superheater [8025], where heat isindirectly removed from the syngas. The HRSG Superheater is preferably ashell and tube type heat exchanger, with the hot syngas travelingthrough the tube-side indirectly contacting steam which is located onthe shell-side. Heat is transferred from the syngas traveling on theequipment's tube-side to the saturated steam that flows through the heatexchanger shell-side, thus generating a source of superheated steam [8]discharged from the shell-side of the Heat Recovery Steam Generator(HRSG) Superheater.

Syngas is transferred from the HRSG Superheater to the Heat RecoverySteam Generator (HRSG) [8050] through HRSG transfer line [10] where thesyngas is further cooled prior to being discharged from the HRSG throughSequence Step C Syngas Discharge [C-OUT]. The HRSG is preferably a shelland tube type heat exchanger, with the syngas on the tube-side and wateron the shell-side. Water [12] is introduced to a HRSG lower shell-sideinlet and used as the heat transfer fluid to remove thermal energy fromthe syngas. A steam and water mixture [14] is generated in theshell-side of the HRSG and transferred to the Steam Drum [8075]. TheSteam Drum is operated under pressure control with a pressuretransmitter [16] acting in communication with a pressure control valve[18] located on the HRSG Superheater shell-side superheated steam [8]discharge line. When pressure control valve [18] opens and releasespressure on automatic pressure control, to maintain a steady pressure inthe Steam Drum, saturated steam is transferred to the HRSG Superheaterthrough saturated steam transfer line [20], where steam indirectlycontacts the syngas flowing through the HRSG Superheater. The Steam Drumis operated under level control where a level transmitter [22] locatedon the vessel acts in communication with a level control valve [24]located on a water supply line [26] to provide water to maintainsufficient level in the Steam Drum to allow recirculation of waterthrough the shell-side of the HRSG. A continuous purge of water flowsfrom the Steam Drum through a steam drum continuous blowdown line [28]to regulate the concentration of suspended and total dissolved solidswithin the volume of water contained within the Steam Drum.

Any type of heat exchange system may be used to achieve the syngascooling functionality prescribed in Sequence Step C. One single heatexchanger may be used, or more than one may be used. Saturated steam maybe generated, as opposed to superheated steam. A forced recirculationHRSG cooling water loop may be used as opposed to the disclosed naturalthermosiphon configuration.

Sequence Step D, Solids Removal & SVOC Removal [D]

Venturi Scrubber

FIG. 4 illustrates Sequence Step D, Solids Removal & SVOC Removal [D],wherein Solids Removal & SVOC Removal Control Volume [D-1] accepts anunconditioned syngas through a Solids & SVOC laden Sequence Step DSyngas Inlet [D-IN], and outputs a first depleted syngas stream, whichhas a reduced amount of solids and SVOC relative to the unconditionedsyngas, through a Solids & SVOC-depleted Sequence Step D SyngasDischarge [D-OUT].

Although any commercially available system capable of removing solidsand SVOC from syngas may be employed, the specific combination andconfiguration of equipment and assets, and methods of operation,disclosed herein, indicate the preferred system to be utilized.

Two separate block process flow drawing configurations for SolidsRemoval & SVOC Removal Control Volume [D-1] are disclosed in theaccompanying text. These are Option 1 and Option 2 as illustrated inFIG. 4, and FIG. 9, respectively. FIG. 5 together with FIG. 6 clarifydetails of preferred Option 1 of Sequence Step D.

Cooled unconditioned syngas is routed to a wetted throat VenturiScrubber [8100] through Sequence Step D Syngas Inlet [D-IN]. The VenturiScrubber operates at a temperature below the SVOC condensationtemperature and below the dew-point of the excess steam contained withinthe syngas therefore condensing said SVOC and excess steam out into aliquid phase. Solid char particulates entrained within the syngas comeinto contact with water provided by a Venturi Scrubber recirculationwater line [30], and solvent provided by a Venturi Scrubberrecirculation solvent line [32], at the divergent section of the VenturiScrubber and said particulates act as a nuclei for excess steamcondensation and are displaced from the vapor phase and into the liquidphase.

Char Scrubber

An intermediate SVOC-depleted syngas containing steam together with afirst mixture comprising SVOC, solids, solvent and water, is routed tothe lower section of the Char Scrubber [8125] via a Venturi Scrubber toChar Scrubber transfer conduit [34]. The Char Scrubber serves as anentrainment separator for the Venturi Scrubber and is configured toreceive the intermediate SVOC-depleted syngas containing steam and thefirst mixture, and separately output a first depleted syngas stream anda second mixture comprising SVOC, solids, solvent and water.

The Char Scrubber, is preferably a vertically oriented cylindrical, orrectangular, pressure vessel having a lower section, and an uppersection, along with a central section that contains a quantity of packedmedia either comprising raschig rings, pall rings, berl saddles, intaloxpacking, metal structured grid packing, hollow spherical packing, highperformance thermoplastic packing, structured packing, synthetic wovenfabric, or ceramic packing, or the like, wherein media is supported upona suitable support grid system commonplace to industrial chemicalequipment systems. The upper section of the scrubber preferably containsa demister to enhance the removal of liquid droplets entrained in avapor stream and to minimize carry-over losses of the sorption liquid.This demister is also positioned above the scrubber spray nozzle system[36], comprised of a plurality of spray nozzles, or spray balls, thatintroduce and substantially equally distribute the scrubbing absorptionliquid to the scrubber onto the scrubber's central packing section so itmay gravity-flow down through the scrubber central section.

As the syngas passes up through the internal packing of the CharScrubber, excess steam within the syngas comes into intimate contactwith water [38] and solvent [40], which are cooled prior to beingintroduced to the upper section of the Char Scrubber through thescrubber spray nozzle system. Steam is condensed into a liquid phasebefore being discharged from the Char Scrubber via the Char Scrubberunderflow downcomer [42].

Intimate gas to liquid contact within the Char Scrubber allows for thesolvent to both, absorb SVOC from the syngas, and enable carboncontained within the char, comprised of a carbon and ash mixture, tobecome oleophilic and hydrophobic permitting said carbon to becomesuspended within the solvent before both the solvent and carbon aredischarged from the Char Scrubber through the Char Scrubber underflowdowncomer [42].

A Char Scrubber Heat Exchanger [8150] is installed in the common waterrecirculation line [44], and is preferably of the shell and tube typeheat exchanger, wherein syngas steam condensate transferred to scrubbingoperations resides on the tube-side, and a cooling water supply [46],and a cooling water return [48], communicate with the shell-side of theheat exchanger to fulfill the heat transfer requirements necessary toindirectly remove heat from the tube-side steam condensate recirculationscrubbing liquid.

Solvent Selection Definition

Where the end syngas user is a FT synthesis reactor, the preferredscrubbing solvent is Medium Fraction Fischer-Tropsch Liquid (MFFTL)generated from the downstream FT catalytic synthesis process, howeverother Fischer-Tropsch products may be used. The ability to generate avaluable scrubbing solvent on-site provides a financial benefit due tooperational self-sufficiency thus improving plant operating costs sincethe facility need not rely upon an outside vendor to furnish thesorption liquid.

Where the end syngas processing technology is a fuels, power, orchemicals production application, the preferred scrubbing solvent is adegreaser solvent, or a biodegradable, non-toxic, and environmentallysafe, industrial cleaning solvent for biodiesel residue, such as BioSolTS 170™, marketed by Evergreen Solutions. Nonetheless, many types ofhydrophilic solvents may be used, including, but not limited to,glycerol, rapeseed methyl ester, biodiesel, canola oil, vegetable oil,corn oil, castor oil, or soy oil, listed in decreasing preference.

Immiscibility Definition

It is to be understood that the water and solvent are immiscible in thatthey are incapable of being mixed to form a homogeneous liquid. Thesolvent phase is relatively less dense than the water phase allowing thesolvent phase to float on top of the water phase. It is also to beunderstood that the solvent possesses a relatively greater affinity forthe unreacted carbon particulate than the water. This is partly due tothe solvent possessing an adhesive tension relative to the carbon solidparticulate exceeding that of water. It is also to be understood thatthe carbon separates immediately and substantially completely from thewater phase and floats on the surface as an unagglomerated fine solidparticulate substance leaving a clear water phase below.

Continuous Candle Filter Decanter

A Continuous Candle Filter Decanter [8175] may be utilized to acceptsyngas excess steam condensate, solvent, and carbon and ash from theChar Scrubber underflow downcomer [42]. The Continuous Candle FilterDecanter is configured to receive the second mixture ash from the CharScrubber underflow downcomer [42] and separate the water within thesecond mixture based upon immiscibility so that the SVOC, solids andsolvent collect together to form a third mixture above the water withinthe decanter vessel, the decanter vessel further configured toseparately output the water and the third mixture.

The Continuous Candle Filter Decanter is comprised of an upright tank[50], made up of two parts, a hollow cylindrical, or rectangular,central section [52] with a closed dome shaped top [54]. It has one ormore conical lower sections [56 a & 56 b] each terminating at the bottomin a drain port with a suitable drain valve [58 a & 58 b] and a drainline [60 a & 60 b]. These drain lines may be connected to a separatecommercially available Filter Cake Liquid Removal System [8225],preferably of a mechanical pressure filter-belt press, or any similardevice that exerts a mechanical pressure on a liquid laden sludge likefilter cake substance to separate liquid therefrom.

A vertical water underflow weir [62] extends downward from the domeshaped top of the upright tank and is spaced away from and cooperateswith the upright vertical housing wall [64] of the hollow center sectionto provide an annular passageway [66] therebetween for passage of thesyngas steam condensate water phase into a common water header [68]taken from various water take-off nozzles [70 a & 70 b],circumferentially positioned around the upper portion of the outerannular passageway. Water may be routed to the water recirculation pump[72] and transferred to the Char Scrubber and Venturi Scrubber. Watertake-off nozzles may be positioned at various points about the uprightvertical housing walls, or water may be pumped from various pointslocated on closed dome shaped top. Only two water take-off nozzles areshown for simplicity, however many more are preferred, usually onetake-off point for each candle filter bundle, wherein a commercialsystem may contain about 4 candle filter bundles.

The vertical water underflow weir is comprised of an upright annularwall that terminates at a height within the pressure vessel deep enoughto provide an inner solvent chamber [74] intended to contain the solventused for recirculation in the scrubbing system. The solvent chamber ispositioned in between the Char Scrubber underflow downcomer [42] and thevertical underflow weir [62]. The solvent and water interface layer iscontained within the inner solvent chamber [76], and therefore thesolvent and water interface rag-layer [78] will also be restricted tothe inner solvent chamber.

It is to be understood that the ‘rag-layer’ describes the region whereinthe solvent and water interface resides, also the location whereunagglomerated carbon may accumulate based on the fact that carbon ismore dense than solvent, thus sinking to the bottom of the solventphase, but being less dense than water, allowing it to float on top ofthe water phase, or at the water and solvent interface layer.

The Char Scrubber underflow downcomer extends from the lower section ofthe Char Scrubber and is disposed within the inner solvent chamberterminating at a height within the solvent chamber at a verticalelevation relatively higher than, and above, the vertical weir underflowheight. It is preferential to operate the system so that the solvent andwater interface rag-layer resides at the region in the solvent chamberwhere the downcomer terminates within the solvent chamber.

The inner solvent chamber, housed within the Continuous Candle FilterDecanter's cylindrical center section, may contain one or more filterbundles [80 a & 80 b] containing a plurality of vertically disposedcandle filter elements [82]. Preferably the elements are of the typewhich possess a perforated metal support core covered with a replaceablefilter cloth, or synonymously termed filter-sock, of woven Teflon clothwith approximate 5-micron pore openings. During filtration, the filtercloth forms a ridged-type structure around the perforated metal core ofthe filter element and, thus ensuring good adherence of the filter cakeduring the filtration phase. Filtrate solvent is conveyed through thefull-length of each individual candle filter element to the filterbundle common register [84 a & 84 b] and to a filtrate removal conduit[86 a & 86 b]. Only two candle filter bundles are shown in the figurefor simplicity. Each filter element is closed at the bottom and allowsfor only circumferential transference of liquid through the filter sockinto the perforations in the metal filter element support core.

A filtrate process pump [88], located on the common filtrate suctionheader [90], sucks solvent from the inner solvent chamber, through eachfilter element [82], of each filter bundle [80 a & 80 b], through eachfilter bundle filtrate removal conduit [86 a & 86 b] and filtrateregister valve [92 a & 92 b], and transfers it via [94] to an optionalSVOC Separation System Control Volume [SVOC-1] where SVOC is removed andan SVOC-depleted solvent is transferred to the Venturi Scrubber and CharScrubber common solvent recirculation line [96].

Pressure transmitters [98 a & 98 b] are installed on each filtrateremoval conduit and may be used to monitor the differential pressureacross each filter bundle in relation to the filter housing pressureprovided by a similar pressure transmitter [100] located on the verticalhousing. In-line flow indicating sight glasses [102 a & 102 b] areinstalled on each filtrate removal conduit so that a plant operator mayvisually see the clarity of the filtrate to determine if any candlefilter sock element has been ruptured and needs repair.

Backflush System

Filtrate Backflush Buffer Tank [8200] accepts SVOC-depleted filtratesolvent from the SVOC-depleted solvent transfer line [104], dischargedfrom the SVOC Separation System. The tank is positioned in communicationwith the SVOC-depleted solvent transfer line [104] and preferably isinstalled in a vertical orientation relative to it so that solvent mayflow via gravity into the tank. The Filtrate Backflush Buffer Tank isequipped with a level transmitter [106] that acts in communication withan solvent supply level control valve [108] located on a solvent supplyline [110] which transfers fresh solvent to the system, either to theFiltrate Backflush Buffer Tank or to the Char Scrubber underflowdowncomer (not shown).

The solvent backflush pump [112] accepts SVOC-depleted filtrate solventfrom the Filtrate Backflush Buffer Tank through filtrate transferconduit [114] and recirculates the solvent back to the FiltrateBackflush Buffer Tank through backflush tank recirculation line [116]. Arestriction orifice [118], or similar pressure letdown device, such asan iris-type adjustable orifice valve, is located in-line to create ahigh pressure recirculation reservoir within the backflush tankrecirculation line [116], and its connected piping network, toaccommodate backflushing of the candle filter bundles.

Candle Filter Operation Philosophy

The best mode of operation for realizing a continuous filtrate streamencompasses operating the filtration system in a manner which allows forperiodic backflushing of the filter element cloth surface in-situ byreversing the flow of liquid scrubbing solvent filtrate through thefilter elements. The backwashing dislodges any accumulated filter cakeallowing it to sink to the bottom of the conical section of the filterhousing for removal of the system as a thick, paste-like, filter cakesubstance. Experimental results have consistently and repeatedly shownthat regeneration of the filter elements to realize sustainable andcontinuous operation of the filter coincides with utilizingSVOC-depleted filtrate solvent as the backflush filter liquid. Howeverthe system will function as intended while utilizing alternate mediumsto cleanse filter element surfaces, such as SVOC laden filtrate solvent,syngas steam condensate, or a vapor source, such as inert nitrogen orcarbon dioxide.

It is preferred to utilize differential pressure across a filter bundleas the main variable to determine when to undergo a back flushing cycle,as opposed to using manual predetermined periodic time durationintervals, or using the reduction in flow through the filter bundles asthe variable dictating when to commence filter back flushing,(synonymously termed ‘filter cleaning’, or ‘filter backwashing’,‘in-situ filter cleaning’, or ‘filter surface in-situ regeneration’).This is because experimental results have shown that a filter bundledifferential pressure between 6 and 10 PSI is commensurate withpreferable cake thickness of 20 to 35 millimeters. In contrast, usingmanual predetermined periodic time duration intervals as the solemechanism to determine when to commence filter cleaning, often resultsin operational impairment, in that ‘cake bridging’ more readily occurs.‘Cake bridging’ is well known in the art of filtration. It may bedescribed as a large mass of agglomerated suspended solids filling thespaces between the filter elements and thus posing a challenge toregenerate in-situ, frequently requiring process interruption forphysical cleaning and removal of the heavy, gelatinous filter cake.

In-situ filter cleaning may be accomplished by reversing the flow ofliquid through the filter element thereby dislodging filter cake fromthe cloth surface thus allowing it to sink to the bottom of the waterphase within the lower filter chamber conical section. This affordsoperations the luxury of minimizing losses of valuable solvent whiledraining the filter cake from the system.

Candle Filter Operating Procedure

FIG. 7 depicts the preferred operating procedure for continuousfiltration of suspended particulate solids from SVOC laden scrubbingsolvent. Filtration [step 950] cooperates with the cyclic-batch filterin-situ cleaning steps of: filter bundle isolation [step 952]; filtratebackflush [step 954]; filter cake sedimentation [step 956]; filter cakedischarge start [step 958]; filter cake discharge end [step 960]; andfiltration restart preparation [step 962].

In step 950, (filtration), filtration proceeds and the filter bundlepressure drop is monitored. As a filtration cycle progresses, solids aredeposited onto the surface of each filter element and adhere to itssurface until a nominal target differential pressure drop between around6 to 10 PSI is attained, which is proportionate to a predeterminedthickness of 20 to 35 millimeters. If the filter bundle pressure drop islower than the nominal target differential pressure drop, the filteringcycle continues until the nominal target differential pressure drop isreached. When a filter bundle has reached its nominal targetdifferential pressure drop, a filter cleaning cycle will commence, whichbegins with step 952 (filter bundle isolation). In addition to FIG. 7,the sequential steps encompassing filtration and filter cleaning can befurther illuminated by using FIG. 6, which visually indicate some of thevalve sequencing involved, as indicated by open and closed valvepositions, illustrated by ‘non-darkened-in valves’ and ‘darkened-invalves’, respectively, of filtrate register valve [92 a & 92 b],backflush filtrate regen valves [120 a & 120 b] (located on respectivefiltrate backflush regen conduits [122 a & 122 b]), as well as filtercake drain valves [58 a & 58 b] located on each lower conical section.FIG. 6, indicates filtrate register valve 92 a open and 92 b closed. Italso shows backflush filtrate regen valves 120 a closed and 120 b open.FIG. 6 further depicts filter cake drain valves 58 b open and 58 aclosed. It should be understood that these valves probably will neveractually be opened at the same time; FIG. 6, together with FIG. 7, offerinsight to the spirit of the operation, to clarify the preferredoperating philosophy, and to provide the reader with a genuineappreciation for the sequencing involved.

When a nominal target pressure drop across a filter bundle is attained,the filter cake material must be dislodged from filter elements of agiven filter bundle, and thus step 952 (filter bundle isolation)proceeds, which involves isolating the relevant filter bundle by closingthe filtrate register valve 92 b to stop filtration on that given filterbundle. Once the filtrate register valve has been closed, to isolate thefilter bundle that exhibits a pressure drop higher or equal to a nominaltarget pressure drop, step 954 may proceed. Step 954, (filtratebackflush), involves transferring filtrate solvent from the pressurizedrecirculation loop [116], provided by the solvent backflush pump [112],through the relevant filtrate back-flush regen conduit [122 b], injectedthough the filtrate regen valve [120 b] where the solvent thencountercurrently enters the filter bundle filtrate removal conduit [86b] and is transferred to the filter elements in need of regeneration.

It is to be understood that the operating discharge pressure of thesolvent backflush pump [116], that required for the filtrate to betransferred countercurrent to operational flow to gently expand thefilter cloth allowing for the cake to be discharged from the filterelement surface, is higher than the operating pressure in the ContinuousCandle Filter's upright tank [50], preferably between 15 to 20 PSIgreater than the filter housing operating pressure, which operatesbetween 30 and 60 PSIG. The pressure difference between the filtratetransferred to the system from the solvent backflush pump [116], and theupright tank [50], is the pressure necessary for the purification of thefilter surfaces. It is to be understood that a typical backflush withSVOC-depleted filtrate solvent, in step 954, requires that the backflushfiltrate regen valve [120 b] need be left open for a duration of timeless than or equal to 10 seconds.

After the SVOC-depleted filtrate solvent has been injected through thefilter bundle, and once the backflush regen valve has been returned to aclosed position, step 956 may commence. Step 956 (filter cakesedimentation) entails allowing a settling time sequence for a durationof time less than or equal to 30 seconds to allow the agglomerateddislodged filter cake solids to sink through both, the solvent phase,and the water phase, thus permitting sufficient time to allow thefiltration induced forcibly agglomerated filter cake solids to settle tothe bottom lower conical drain section.

Step 958 (filter cake discharge start) involves opening the respectiveregenerated filter bundle's filter cake drain valve [58 b] to allowtransference of an agglomerated paste-like carbon particulate filtercake material from the system. The process control signal generationmechanism required to end step 958 involves monitoring the signal outputfrom a presence/absence detection flange mounted instrument [124 b],also termed an impedance-sensing device, or the like, which may beinstalled just upstream prior to the filter cake drain valves to servethe purpose of further automating the system by indicating when thethick paste-like filter cake material has left the system.

Alternately the sensors may be furnished by the commercial vendor todetect the presence or absence of water within the pipeline thus actingas a control mechanism for closing the drain valve. If the processcontrol signal indicates that the filter cake is being drained from thesystem, step 958 continues. If, on the other hand, the process controlsignal indicates that the filter cake has left the system, step 958 willend, and step 960 may begin. Step 960 (filter cake discharge end)entails closing the respective filter cake drain valve [58 b] sincesolids have been discharged from the system. After step 960 hastranspired, step 962 (filtration restart preparation) may commence whichentails opening the respective filter bundle's filtrate register valve[92 b] to again commence filtration on the regenerated filter bundle,thus allowing step 950 to commence again, then allowing the filtrationand regeneration cycle to repeat itself.

Filter Cake Liquid Removal System

After the filter cake material is removed from the candle filter vessel,it may be transferred to any sort of commercially available Filter CakeLiquid Removal System [8225], preferably a belt filter press, or anysimilar device which applies mechanical pressure to an agglomeratedsludge paste-like filter cake to remove residual liquid therefrom.Liquid removed from the filter cake [124] may be transferred to theplant waste water header, whereas the liquid depleted solids [126] maybe transferred to another location for Liquid Depleted Solids Collection[8250].

Step D, Option 1, Operation

FIG. 8 underlines the principles dictating the philosophy of operationof Option 1 of Solids Removal & SVOC Removal Control Volume [D-1] asdepicted in FIG. 4, which are as follows:

Step D1 a:

-   -   contacting the unconditioned syngas with a solvent and water to        reduce the temperature of the syngas to below the SVOC        condensation temperature to thereby form an intermediate        SVOC-depleted syngas containing steam, and a first mixture        comprising SVOC, solids, solvent and water;

Step D1 b:

-   -   removing steam from the intermediate SVOC-depleted syngas        containing steam to form: (i) a first depleted syngas stream        which has a reduced amount of SVOC relative to the unconditioned        gas stream, and (ii) a second mixture comprising SVOC, solids,        solvent and water;

Step D1 c:

-   -   separating the water within the second mixture based upon        immiscibility so that the SVOC, solids and solvent collect        together to form a third mixture above the water; separating the        solids from the SVOC and solvent in a vessel having at least one        liquid phase candle filter such that the solids agglomerate on a        surface of the candle filter and form a filter cake having        density greater than that of water within the vessel;

Step D1 d:

-   -   Backflushing the candle filter to loosen the filter cake so that        the filter cake sinks into the water within the vessel; and

Step D1 e:

-   -   Removing the filter cake from a bottom of the vessel.        Step D, Option 2

In an alternate, non-limiting embodiment, the immiscible liquidseparation and continuous filtration functionalities of the ContinuousCandle Filter Decanter [8175] may be decoupled.

Option 2 of Solids Removal & SVOC Removal Control Volume [D-1], asdepicted in FIG. 9 and FIG. 10, utilizes a Decanter [8275] andContinuous Candle Filter [8300], which serve a similar function as theContinuous Candle Filter Decanter [8175]. Separation of immiscibleliquids followed by separation of SVOC from the solvent filtrate is theguiding principle to be achieved by installation of the configurationdisclosed in Option 2.

The purpose of the Continuous Candle Filter Decanter [8175], of Step DOption 1, is to combine the functionality of density separation ofliquids together with filtration separation of solids from liquids. Itfurther automates an otherwise batch-wise filter operation so that acontinuous cyclic-batch system is realized. As illustrated in FIG. 9,the Decanter [8275] and Continuous Candle Filter [8300] are separatefrom one another.

FIG. 9 depicts the Decanter [8275] and Continuous Candle Filter [8300]in communication through a solids & SVOC laden solvent filtrate transferline [128]. It further depicts the Continuous Candle Filter [8300] incommunication with the SVOC Separation System Control Volume [SVOC-1]through a SVOC laden solvent filtrate transfer line [130].

Decanters are well known liquid density separation unit operationscommonplace to commercial industrial systems. Furthermore, similarly,candle filters, or the like, are commercially available and theirinstallation, integration, and operation are well known to a personpossessing an ordinary skill in the art to which it pertains.

FIG. 10 outlines the principles dictating the philosophy of operation ofOption 2 of Solids Removal & SVOC Removal Control Volume [D-1] asdepicted in FIG. 9, which are as follows:

Step D1 a:

-   -   contacting the unconditioned syngas with a solvent and water to        reduce the temperature of the syngas to below the SVOC        condensation temperature to thereby form an intermediate        SVOC-depleted syngas containing steam, and a first mixture        comprising SVOC, solids, solvent and water;

Step D1 b:

-   -   removing steam from the intermediate SVOC-depleted syngas        containing steam to form: (i) a first depleted syngas stream        which has a reduced amount of SVOC relative to the unconditioned        gas stream, and (ii) a second mixture comprising SVOC, solids,        solvent and water;

Step D1 ca:

-   -   Separating the water within the second mixture based upon        immiscibility so that the SVOC, solids and solvent collect        together to form a third mixture above the water;

Step D1 cb:

-   -   separating the solids from the SVOC and solvent in a vessel        having at least one liquid phase candle filter such that the        solids agglomerate on a surface of the candle filter and form a        filter cake having density greater than that of water within the        vessel;

Step D1 d:

-   -   Backflushing the candle filter to loosen the filter cake so that        the filter cake sinks into the water within the vessel; and

Step D1 e:

-   -   Removing the filter cake from a bottom of the vessel.        SVOC Separation System

FIG. 11 and FIG. 12 illustrate options for separating SVOC from thefiltrate scrubbing solvent.

SVOC Flash Separation System

The preferred application to remove SVOC from the syngas as depicted inSolids Removal & SVOC Removal Control Volume [D-1], encompasses theutilization of a scrubbing solvent that sorbs SVOC from the syngas. SVOCremoval from the scrubbing solvent must take place in order to realizecontinuous recycle of the scrubbing solvent as well as to avoid thebuildup of SVOC within the system leading to operational impairment ofthe scrubbing operations.

In order to continuously recycle absorption scrubbing liquid, a SVOCFlash Separation System, as depicted in FIG. 11, may be employed toflash SVOC from the scrubbing solvent. Preferably this system isemployed together with the use of a vacuum system, condenser system, andliquid SVOC collection equipment permitting the recovery of a SVOCproduct.

FIG. 11 depicts the preferred non-limiting embodiment for the SVOCSeparation System Control Volume [SVOC-1]. SVOC laden filtrate scrubbingsolvent is transferred from solvent and char filtration operationsthrough a filtrate solvent transfer line [94] and routed to the inlet ofa SVOC Flash Tank Heat Exchanger [8325], which is preferably of a shelland tube type heat exchanger. Steam, or another heat source, maycommunicate with the shell-side of the heat exchanger through a steaminlet line [132] and a steam discharge line [134] to transfer heat tothe SVOC laden filtrate solvent traveling through the exchanger'stube-side prior to being transferred to the SVOC Flash Tank [8350]. SVOCladen filtrate scrubbing solvent is discharged from the exchanger'stube-side and routed through a SVOC laden filtrate solvent Flash Tanktransfer line [136] where it then flows through a pressure letdowndevice [138], comprised of either a valve, or restriction orifice, thatis positioned just upstream of the inlet to the SVOC Flash Tank. Uponrelease to the lower pressure environment of the SVOC Flash Tank, theSVOC liquid fraction is vaporized, or flashed, from the SVOC ladenfiltrate solvent and enters the SVOC flash transfer conduit [140] forcondensation and collection of the SVOC product. A SVOC-depletedfiltrate solvent is expelled from the lower section of the SVOC FlashTank where it enters a SVOC-depleted solvent transfer line [142]. ASVOC-depleted solvent transfer pump [144], routes the solvent to aSolvent Cooler [8375] through a solvent transfer line [146], or it maytransfer the solvent back to the SVOC Flash Tank Heat Exchanger [8325]through a solvent recycle line [148].

A cooling water supply [150] and a cooling water return [152]communicate with the shell-side of the Solvent Cooler [8375] and providethe thermal capacity to remove heat from the solvent traveling throughthe tube-side of the exchanger.

The SVOC Flash Tank is preferably a vertical cylindrical tank, howeverit may be a horizontal flash tank with provided distribution pipe, andmay be equipped with an impingement baffle [154] to provide a suddenflow direction change of the flashing SVOC laden filtrate solvent. Aplurality of spray nozzles [156] are positioned in the upper section ofthe SVOC Flash Tank and are utilized for intermittent washing with aclean in place (CIP) agent transferred to the system through a CIP agenttransfer line [158] and a CIP agent isolation valve [160]. Cleaning ofthe vessel preferably is performed only when the solvent is isolatedfrom the SVOC Flash System. The spray nozzles [156] may also be providedwith a source of cooled SVOC-depleted solvent through a cooledSVOC-depleted solvent transfer line [162] routed from the discharge ofthe Solvent Cooler [8375].

The SVOC Flash Tank Heat Exchanger [8325] increases the temperature ofthe SVOC laden solvent stream to above the flash point of SVOC andlesser than, and not equal, to the flash point temperature of thescrubbing solvent. This is to permit vaporization of only the SVOCfraction within the solvent and SVOC liquid mixture upon release to alower pressure across the pressure letdown device [138].

A SVOC Condenser [8400] accepts SVOC laden vapors from the SVOC vaportransfer conduit [140] and condenses the SVOC into a liquid state priorto discharging the liquid SVOC from the system through a SVOC SeparationSystem Control Volume SVOC Discharge [SVOC-OUT].

A SVOC vacuum system transfer line [164] connects the SVOC Vacuum System[8425], with the SVOC Condenser [8400]. The Vacuum system is preferablya liquid ring vacuum pump that uses a liquid SVOC seal fluid [166]within its pump casing (not shown).

A cooling water supply [170] and a cooling water return [172]communicate with the shell-side of the SVOC Condenser [8400] and providethe thermal capacity to condense SVOC traveling through the tube-side ofthe exchanger into a liquid phase.

SVOC Membrane Separation System

In an alternate non-limiting embodiment, selective sorptive permeationof SVOC from the scrubbing liquid may be employed, as depicted in FIG.12 which portrays the SVOC Sorptive Separation System. Liquid phasesorption applications, not only including pervaporation membraneprocesses, may be employed to separate the SVOC from the SVOC ladenscrubbing solvent liquid mixture due to selective diffusion of the SVOCmolecules based on molecular diameter and polarity.

SVOC laden filtrate scrubbing solvent may be transferred from thefiltrate solvent transfer line [94] to the inlet of a SVOC SorptiveSeparator [8475]. It is preferred to utilize a SVOC Sorptive Separator[8475] in a capacity to realize liquid phase pervaporative sorptionseparation of SVOC from a solvent laden filtrate stream. However apacked bed of adsorbent, either polymeric styrene based adsorbents, or10 angstom aluminosilicate molecular sieve adsorbents, or a suitablesorption medium possessing an preferential sorption of SVOC from ascrubbing solvent may also be utilized to accomplish a similar result.

The SVOC Sorptive Separator [8475] is preferentially comprised of acommercially available permeation unit, preferably a shell and tubedevice utilizing a tubular membrane selective to hydrophobic non-polarsolvents preferably in the form of a PEEK based membrane cast inside ahollow fiber tube.

The SVOC Sorptive Separator [8475] may also contain a cluster ofmembrane elements, and more than one permeation unit may be used tocreate multiple pervaporation modules, or even multiple stages ofpervaporation modules may be utilized. Although a plate and frame typeunit may be utilized in conjunction with membrane sheets, the shell andtube type system is preferred due to its ease in manufacture and lowercapital cost.

The SVOC Sorptive Separator [8475] contains a porous membrane [174],preferably with a porous chemical resistant coating [176], having a SVOCladen solvent membrane process surface [178 a], that is exposed to theSVOC laden filtrate scrubbing solvent, and an opposing SVOC permeatemembrane process surface [178 b], where the SVOC permeate is volatilizedtherefrom by a driving force created by preferably a combination of avacuum driven and a temperature driven gradient created by a downstreamvacuum system and condenser as previously described.

A Guard Filter [8450] accepts SVOC laden filtrate solvent from thefiltrate solvent transfer line [94] prior to routing it to the SVOCSorptive Separator [8475] through a second filtrate solvent transferline [180]. The Guard Filter [8450] is in place to mediate any membranefouling which may arise due to fine particulate matter blocking membraneflow channels, contributing to clogging of effective membrane voidspaces and ultimately causing a gradual decline in the membrane SVOCpermeation rate. The Guard Filter [8450] is preferably an easy accessmetal filter-bag housing preferably containing a heavy-duty polyesterfelt filter bag of 0.5 micron effective pore size.

Sequence Step E, Chlorine Removal [E]

FIG. 13 illustrates Sequence Step E, Chlorine Removal [E], whereinChlorine Removal Control Volume [E-1] accepts a chlorine laden SequenceStep E Syngas Inlet [E-IN], and outputs a chlorine depleted SequenceStep E Syngas Discharge [E-OUT].

The Chlorine Scrubber [8500], configured similar to the Char Scrubber[8125], is also a vertically oriented cylindrical, or rectangular,pressure vessel having a lower section, and an upper section, along witha central section that contains a specified quantity of packedabsorption media, which is supported upon a suitable support grid systemcommonplace to industrial chemical equipment systems. The upper sectionof the scrubber preferably contains a demister that is positioned abovea scrubber spray nozzle system [236] which introduces the scrubbingabsorption liquid to the scrubber.

The purpose of the Hydrogen Chloride Scrubber is to remove trace amountsof hydrogen chloride from the syngas by using water condensed fromresidual steam contained within the syngas as the main scrubbingabsorption liquid. It also serves the function to remove any residualparticulate elutriated in the syngas.

Syngas enters the lower section of the Hydrogen Chloride Scrubber andpasses up through the scrubber's central section where the syngas vaporcomes into intimate contact with the water scrubbing liquid travelingcountercurrently via gravity flow down through the scrubber's packing.Water is condensed out of the vapor phase and enters the lower sectionof the scrubber. A level control loop, comprising a level transmitter[200], positioned on the lower section of the scrubber, and a levelcontrol valve [202], may be automatically operated to permit water to bebled from the scrubber water recirculation piping [238], via a wastewater transfer conduit [240], to maintain a steady liquid level withinthe lower section of the scrubber. A scrubber water recirculation pump[276], accepts water from the lower section of the scrubber, through thepump suction piping [242], and transfers the water through a HydrogenChloride Scrubber Heat Exchanger [8525], prior to injecting the waterinto the scrubber, via the main recirculation piping [238], which routesthe water through the scrubber's spray nozzle system [236] and into theupper section of the scrubber where the flow of liquid is directeddownwards onto the scrubber central packing. The Hydrogen ChlorideScrubber Heat Exchanger [8525] is preferably of the shell and tube type,wherein a cooling water supply [246], and a cooling water return [248],communicate with the shell-side of the heat exchanger to fulfill theheat transfer requirements necessary to indirectly remove heat from theprocess side steam condensate recirculation liquid. Process water [214]may be transferred to the scrubber water recirculation piping, or thelower section of the scrubber.

Sequence Step F, Sulfur Removal [F]

FIG. 14 illustrates Sequence Step F, Sulfur Removal [F], wherein SulfurRemoval Control Volume [F-1] accepts a sulfur laden Sequence Step FSyngas Inlet [F-IN], and outputs a sulfur-depleted Sequence Step FSyngas Discharge [F-OUT].

The Sulfur Scrubber [8550] is configured similar to the ChlorineScrubber [8500]. The upper section of the scrubber preferably contains ademister that is positioned above a scrubber spray nozzle system [336]which introduces the scrubbing absorption liquid to the scrubber. Syngasenters the lower section of the Sulfur Scrubber and passes up throughthe scrubber's central section where the syngas vapor comes intointimate contact with a hydrogen sulfide scavenger scrubbing liquidtraveling countercurrently via gravity flow downward through thescrubber's packing. The Sulfur Scrubber preferentially utilizes ahydrogen sulfide scavenger as the main scrubbing fluid which ispreferably a dilute, nonregenerable, water-soluble, triazine derivedsolution, preferably of Nalco EC9021A product, diluted with water tobetween a 0.01 and 1 wt % triazine solution mixture. Glyoxal from BASF,SE-100 H2S Hydrogen Sulfide Scavenger from Sepcor, DTM Triazine fromDThree Technology, or Baker Hughes' Petrolite SULFIX™ H2S scavengers mayalternately be used. The use of a regenerable hydrogen sulfide scavengerfluid may also be used.

The Sulfur Scrubber is equipped with a level transmitter [300],positioned on the lower section of the scrubber, which cooperates with alevel control valve [302] located on a waste transfer conduit [340]. Therecirculation pump [376] accepts a dilute triazine solution from thelower section of the scrubber, through its pump suction piping [342],and pumps the liquid to the upper section of the scrubber through therecirculation piping [338] and through a plurality of spray nozzleswhich spray the flow downwards onto the scrubber's centrally locatedpacked section.

A source of process water [314], along with a source of a freshconcentrated sulfur scavenger derived solution [316], are available tobe injected into the Sulfur Scrubber system, preferably into therecirculation piping [338].

Any type of sulfur removal system may be used to achieve the syngascooling functionality prescribed in Sequence Step F. Some alternativesmay be, including, but not limited to, wet limestone scrubbing systems,spray dry scrubbers, claus processing system, solvent based sulfurremoval processes such as the UC Sulfur Recovery Process (UCSRP),low-temperature or refrigerated solvent-based scrubbing systems usingamines or physical solvents (i.e., Rectisol, Selexol, Sulfinol), hightemperature sorbents, glycol ether, diethylene glycol methyl ether(DGM), regenerable and non-regenerable sorbents, molecular sievezeolites, calcium based sorbents, FeO, MgO or ZnO-based sorbents orcatalysts, Iron Sponge, potassium-hydroxide-impregnated activated-carbonsystems, impregnated activated alumina, titanium dioxide catalysts,vanadium pentoxide catalysts, tungsten trioxide catalysts, sulfurbacteria (Thiobacilli), sodium biphospahte solutions, aqueous ferriciron chelate solutions, potassium carbonate solutions, alkali earthmetal chlorides, magnesium chloride, barium chloride, crystallizationtechniques, bio-catalyzed scrubbing processes such as the THIOPAQScrubber, or hydrodesulphurization catalysts.

Sequence Step G, Particulate Filtration [G]

FIG. 15 illustrates Sequence Step G, Particulate Filtration [G], whereinthe Particulate Filer [8575] situated within the Particulate FiltrationControl Volume [G-1] accepts a particulate laden Sequence Step G SyngasInlet [G-IN], and outputs a particulate depleted Sequence Step G SyngasDischarge [G-OUT].

Sequence Step H, Syngas Compression [H]

FIG. 16 illustrates Sequence Step H, Syngas Compression [H], wherein theSyngas Compressor [8600] accepts a Sequence Step H Syngas Inlet [H-IN],and outputs a Sequence Step H Syngas Discharge [H-OUT]. A gaseoushydrocarbon source [HC-IN] may be optionally routed to the inlet of theSyngas Compressor [8600] and may include, natural gas, syngas, refineryoffgases, naphtha, methanol, ethanol, petroleum, methane, ethane,propane, butane, hexane, benzene, toluene, xylene, or naphthalene, orthe like.

Sequence Step I, VOC Removal [I]

FIG. 17 depicts Sequence Step I, VOC Removal [I], wherein VOC RemovalControl Volume [I-1] accepts a VOC laden Sequence Step I Syngas Inlet[I-IN], and outputs a VOC-depleted Sequence Step I Syngas Discharge[I-OUT].

VOC removal systems are not conventionally found within syngas cleaningor conditioning processes. Experimental results have consistently andrepeatedly shown that without Sequence Step I, VOC Removal [I] in placesulfur removal systems could be inhibited downstream allowingcontaminants to pass through the system and poison catalysts that arenot sulfur tolerant.

In one non-limiting embodiment, VOC may be removed from syngas byutilizing a heat exchange adsorption process that combines thermal swingregeneration with vacuum pressure swing adsorption (VPSA), as depictedin FIG. 18.

In another non-limited embodiment, VOC may be removed from syngas byutilizing a fluidized particulate bed adsorption system wherein VOCsaturated adsorbent is regenerated utilizing a vacuum assisted thermalswing desorption process as depicted in FIG. 19.

Sequence Step I, Option 1

FIG. 18 depicts Option 1 of Sequence Step I which discloses a separationsystem that may be used to remove VOC from syngas. The figure portrays aVPSA system with thermal swing desorption capabilities.

VPSA is a gas separation process in which the adsorbent is regeneratedby rapidly reducing the partial pressure of the adsorbed component,either by lowering the total partial pressure or by using a purge gas.

In a VPSA system, regeneration is achieved by first stopping feed flow,then depressurizing the adsorbent, usually by passing regeneration gasthrough the bed counter-current to the feed direction. The regeneratinggas is generally free of impurities.

VPSA systems have certain inherent disadvantages, mostly attributed tothe short cycle time that characterizes VPSA. In each cycle ofoperation, the adsorbent is subjected to a feed period during whichadsorption takes place, followed by depressurization, regeneration, andrepressurization. During the depressurization, the feed gas in the bedis vented off and lost, which is referred to as a “switch loss.” Theshort cycle time in the VPSA system gives rise to high switch lossesand, because the cycle is short, it is necessary that therepressurization is conduced quickly. This rapid repressurization causestransient variations in the feed and product flows, which can adverselyaffect the plant operation, particularly in the operation of processesdownstream of the adsorption process.

VPSA is best used for components that are not too strongly adsorbed. Onthe other hand, thermal swing adsorption (TSA) is preferred for verystrongly adsorbed components, since a modest change in temperatureproduces a large change in gas-solid adsorption equilibrium. In thetemperature swing process, to achieve regeneration, is it necessary tosupply heat to desorb the material. Following regeneration of thesorbent by heating, the sorbent preferably is cooled prior to the nextadsorption step, preferably by transferring a cooling fluid, not onlyincluding water, through the thermal transfer chambers of each AromaticHydrocarbon Micro-Scale Heat Exchange Adsorber [8625A&B].

In one embodiment, each Aromatic Hydrocarbon Micro-Scale, also termedMicrochannel, Heat Exchange Adsorber [8625A&B] includes one or moreadsorption chambers [402] each of which may be tubular or rectangular inshape and each chamber is separated from the adjacent chamber(s) by athermal transfer chamber [404]. Each adsorption chamber is provided witha feed inlet [406 a & 406 b] for introducing VOC laden syngas, a productoutlet [408 a & 408 b] for removing VOC-depleted syngas from theadsorption chamber, and a particulate bed [410] comprising sorbentparticles disposed within the chamber. It is desirable for theadsorption chambers to be relatively narrow to ensure rapid heattransfer, and thus is it our realization that a micro-scale heatexchanger, also termed a microchannel heat exchanger, is the preferredunit operation to be utilized in this particular application. In anothernon-limiting embodiment, each Aromatic Hydrocarbon Adsorber [8625A&B]are comprised of fixed beds without thermal transfer chambers [404]. Itis to be understood that although FIG. 18 depicts parallel first andsecond adsorbers capable of being operated such that while the firstheat exchange adsorber is in an adsorption mode, the second heatexchange adsorber is in a regeneration mode, more than two adsorbers maybe used so that one adsorber is off-line.

The particulate bed preferably contains an adsorption medium thatselectively adsorbs VOC into the pores of adsorbent versus any othersyngas constituents. In one embodiment, the adsorbent is a styrene basedpolymeric adsorbent, such as Dowex Optipore V503, or the like. Inanother embodiment, the adsorbent may be made up of molecular sieves,zeolites, catalyst materials, silica gel, alumina, activated carbonmaterials, or combinations thereof.

Each thermal transfer chamber is equipped with thermal transfer chamberinlet valve [412 a & 412 b]. A coolant material, not only includingwater, or a heating material, not only including steam, may beintroduced into the thermal transfer chamber. The coolant material mayremove heat from the adjacent adsorption chambers by thermal transfer.The heating material can add heat to the adjacent adsorption chambersalso by thermal transfer.

When the first adsorber unit [8625A] is in an adsorption mode, thesecond adsorber [8625B] is in regeneration mode where the secondadsorber is first depressurized, then purged with the VOC-depletedsyngas stream and finally re-pressurized. During this part of the cycle,the first inlet valve [414 a] is open and the second first inlet valve[414 b] is closed directing the syngas feed from line [I-IN] into thefirst adsorber [8625A]. As the VOC laden syngas passes through theadsorber [8625A], VOC adsorbate is selectively adsorbed into the poresof the adsorbent and the VOC-depleted syngas passes through a firstproduct outlet valve [416 a] and transferred from the VOC separationsystem through Sequence Step I Syngas Discharge [I-OUT]. During theentire regeneration process, second product outlet valve [416 b] isclosed to prevent flow of regenerate into the VOC-depleted syngasstream.

Under regeneration conditions, the second adsorber [8625B] is firstdepressurized. During depressurization, both the first purge inlet valve[418 a] and second purge inlet valve [418 b] are closed to prevent purgefrom entering the second adsorber [8625B] during depressurization. Thefirst depressurization valve [420 a] is closed to prevent flow of theVOC laden syngas stream [I-IN] into the regenerate product line [430].The first thermal transfer chamber inlet valve [412 a] is closed toprevent heat addition to the first adsorber [8625A] undergoingadsorption, and the second thermal transfer chamber inlet valve [412 b]on the second adsorber [8625B] is open to allow transfer of heat to theregenerating VOC saturated adsorbent. The second depressurization outletvalve [420 b] is open allowing flow from the second adsorber [8625B]through the regenerate product line [430]. The regenerate product willcontain a mixture of syngas and VOC. The regenerate product line isunder a vacuum condition as a result of the VOC Vacuum System [8675].The regenerate product flows freely from the pressurized second adsorber[8625B] along the regenerate product line [430].

Once the second adsorber is fully depressurized, the second purge inletvalve [418 b] is opened allowing flow of VOC-depleted syngas to purgethe VOC that is selectively adsorbed in the pores of the adsorbent andwithdraw such purge stream along regenerate product line [430] undervacuum conditions. Simultaneous to the time when the purge inlet valveis opened, the second adsorber's thermal transfer chamber inlet valve[412 b] is opened to indirectly transfer thermal energy to thedepressurized regenerating adsorber [8625B] to aide the removal of VOCadsorbate from the pores of the adsorbent which is under vacuumconditions. Once the purge and heat addition steps are complete for thesecond adsorber [8625B], depressurization outlet valve [420 b] is closedwhile purge inlet valve [418 b] remains open so that VOC-depleted syngasfrom the first adsorber [8625A] can pressurize the second adsorber[8625B] to the same pressure as the first adsorber [8625B]. Coolant maybe exchanged for the heat source transferred to the second adsorber[8625B] through the second thermal transfer chamber inlet valve [412 b]and into the thermal transfer chamber [404] of the second adsorber[8625B] to cool the adsorbent media within the adsorption chamber toprepare it for the next adsorption sequence.

Once the second adsorber [8625B] is fully pressurized, it is ready forits function to switch from regeneration to adsorption. At this point,the adsorbent in the first adsorber [8625A] has selectively adsorbed aconsiderable amount of VOC. The first adsorber [8625A] is ready forregeneration. The two beds switch function. This occurs by the followingvalve changes. The first product outlet valve [416 a] is closed, and thefirst inlet valve [414 a] is closed. The first purge inlet valve [418 a]remains closed, and the first depressurization outlet valve [420 a] isopened to begin depressurization of the first adsorber [8625A]. Thesecond thermal transfer chamber inlet valve [412 b] is closed and thefirst thermal transfer chamber inlet valve [412 a] is opened to allowthermal energy to be transferred to the first adsorber [8625A] thermaltransfer chamber [404].

Adsorption begins for the second adsorber [8625B] with the followingvalve arrangement. The second depressurization outlet valve [420 b]remains closed. The second purge inlet valve [418 b] is closed. Thesecond product outlet valve [416 b] is opened, and the first inlet valve[414 b] is opened to facilitate flow from the VOC laden syngas stream[I-IN] into the second adsorber and flow of VOC-depleted syngas from thesecond adsorber [8625B] through second product outlet valve [416 b] intothe VOC-depleted syngas stream [I-OUT]. The regeneration process asdescribed above for the second adsorber [8625B] is repeated for thefirst adsorber [8625A].

Preferably, the regeneration occurs at a pressure below atmosphericpressure under a vacuum created by the VOC Vacuum System [8675]. Theregenerate leaves the second adsorber [8625B] as a vapor stream. It iscooled in a VOC Condenser [8650] supplied with a cooling water supply[470] and a cooling water return [472]. Condensed VOC regenerate productis withdrawn along stream through VOC Separation System Control VolumeVOC Discharge [VOC-OUT].

A VOC vacuum system transfer line [464] connects the VOC Vacuum System[8675], with the VOC Condenser [8650]. The Vacuum system is preferably aliquid ring vacuum pump that uses a liquid VOC seal fluid [466] withinits pump casing (not shown).

This system is preferably operated during adsorption at a pressure of 25psia of greater and preferably 300 psia of greater. The VPSA systemduring regeneration of the bed, in one embodiment, is operated at lessthan atmospheric pressure. In one embodiment, the VPSA system isoperated at a pressure of 7.5 psia or less and preferably 5 psia or lessto regenerate the bed. In one embodiment, the VPSA system uses a two bedsystem. Optionally a three bed system is used. In another embodiment,four or more beds are used.

Sequence Step I, Option 2

In another non-limiting embodiment, VOC may be removed from syngas byutilization of a continuous pressurized fluidized particulate bedadsorption system whereby VOC laden syngas is used to fluidize aparticulate bed containing an adsorption medium that selectively adsorbsVOC.

FIG. 19 depicts, Sequence Step I, VOC Removal [I], Option 2 as theembodiment situated within VOC Removal Control Volume [I-1]. An AromaticHydrocarbon Fluidized Sorption Bed [8700] accepts VOC laden syngas fromstream [I-IN] and outputs a VOC-depleted syngas through stream [I-OUT].

VOC laden syngas is introduced into the Aromatic Hydrocarbon FluidizedSorption Bed [8700] through a distribution plate [474], which may bepositioned below an optional support grid system [476] with a suitablescreen to prevent reverse-flow of absorbent into the inlet conduit[I-IN].

Syngas fluidizes the adsorbent bed material [478] which adsorbs VOC fromthe vapor bubbles [480] passing up through the bed. An optional internalcyclone [482] may be positioned within the freeboard section [484] ofthe fluidized bed to separate the adsorbent from the VOC-depletedsyngas, and return the adsorbent to the bed via a cyclone dipleg [486].

Desorption of VOC from the VOC saturated adsorbent takes place withinthe indirectly heated Regen Heat Exchange Fluidized Bed [8725]. In orderfor the Aromatic Hydrocarbon Fluidized Sorption Bed [8700] to realize acontinuous separation of VOC from syngas, adsorbent bed material [478]must be moved from the bed, regenerated, and then transported back tothe bed. A series of alternating solids handling valves [490 a & 490 b],configured in a lock hopper arrangement, may be used to batch-transfervolumes of adsorbent bed material [478] through VOC adsorbent transferconduit [488] to the Regen Heat Exchange Fluidized Bed [8725]. Lockhopper valve arrangements are well known in the art to which it pertainsand are commonly used to transfer solids from one isolated pressurizedenvironment to another.

Sequence Step I, VOC Removal [I], Option 2 is preferentially installedprior to Syngas Compression Sequence Step [H]. Therefore, the preferredoperating pressure range for the Aromatic Hydrocarbon Fluidized SorptionBed [8700] of Sequence Step I, Option 2 ranges from 30 to 75 psia. Theregenerate product line [430] connected to the Regen Heat ExchangeFluidized Bed [8725] is held under vacuum conditions as described inFIG. 18. The Regen Heat Exchange Fluidized Bed [8725] is operated undervacuum conditions at a pressure 14.5 psia or less and preferably 8.5psia or less.

The Regen Heat Exchange Fluidized Bed [8725] is continuously fluidizedwith a VOC-depleted vapor source [492], preferably with FT tailgas,however, steam, compressed syngas, or any other available vapor, such asnitrogen or air may be used instead.

The VOC-depleted vapor source [492] is introduced into the Regen HeatExchange Fluidized Bed [8725] through a distribution plate [494], whichmay be positioned below an optional support grid system [496] with asuitable screen. A heat source [498], preferably steam, is madeavailable to at least one heat transfer chamber [500] that shares atleast one heat transfer surface [502] with that of the fluidizedadsorbent bed material [478] contained within the Regen Heat ExchangeFluidized Bed [8725]. This allows thermal energy to be indirectlytransferred into the bed to allow a temperature aided desorption of VOCfrom the pores of the adsorbent material that is fluidized with theVOC-depleted vapor source [492]. VOC will be released from the adsorbentmaterial within the bed and will enter the vapor bubbles [504] as theypass up through the bed.

An optional internal cyclone [508] may be positioned within thefreeboard section [512] of the fluidized bed to separate the adsorbentfrom the VOC laden vapor, and return the adsorbent to the bed via acyclone dipleg [514]. A series of alternating solids handling valves[516 a & 516 b], configured in a lock hopper arrangement, may be used tobatch-transfer volumes of regenerated adsorbent bed material [478]through transfer conduit [518] to the Sorbent Transfer Tank [8750].

The Sorbent Transfer Tank [8750] is a cylindrical pressure vesselequipped with a dip tube [520], pressurized vapor source [522], andsolids handling valves [524 a & 524 b], which are used together incombination to transport regenerated adsorbent bed material [478] backto the Aromatic Hydrocarbon Fluidized Sorption Bed [8700] through regenadsorbent transport line [526]. Regenerated adsorbent bed material [478]is first transferred from the Regen Heat Exchange Fluidized Bed [8725]to the Sorbent Transfer Tank [8750] through solids handling valves [516a & 516 b]. The Sorbent Transfer Tank [8750] is the isolated andpressurized with the vapor source [522] by opening solids handling valve[524 a] while valve 524 b is closed. When the pressure in the SorbentTransfer Tank [8750] exceeds that of the Aromatic Hydrocarbon FluidizedSorption Bed [8700], the valve positions of solids handling valves [524a & 524 b] are switched allowing regenerated adsorbent bed material[478] to be conveyed via a pressure surge from the Sorbent Transfer Tank[8750] up through the dip tube [520], and through the regen adsorbenttransport line [526], where it may then enter the Aromatic HydrocarbonFluidized Sorption Bed [8700]. The regenerated adsorbent bed material[478] may either free fall through the freeboard section [484], or ifperforated trays [528] are installed in the freeboard section [484], theregenerated adsorbent bed material [478] may gradually trickle downthrough the vessel and thus improve gas to solid contact.

In another non-limiting embodiment, the Regen Heat Exchange FluidizedBed [8725] may be operated under positive pressure conditions whereinVOC may be condensed and recovered as disclosed in FIG. 18. In thisparticular embodiment, a VOC laden gaseous hydrocarbon vapor [430] maythen exit the Regen Heat Exchange Fluidized Bed [8725], where it thenmay be made available as a fuel source to the Hydrocarbon Reformer[8000] of Sequence Step B, Hydrocarbon Reforming [B].

Sequence Step J, Metal Removal [J]

FIG. 20 depicts Sequence Step J, Metal Removal [J], wherein MetalRemoval Control Volume [J-1] accepts a metal laden Sequence Step JSyngas Inlet [J-IN], and outputs a metal depleted Sequence Step J SyngasDischarge [J-OUT].

Metal Guard Bed [8775] is preferably comprised of vertical cylindricalpressure vessel containing cellulose acetate packing media possessing anaffinity to sorb heavy metals, not only including, mercury, arsenic,lead, and cadmium. The cellulose acetate may be in the form of beads,spheres, flake, or pellets. Alternatively, sorbents such as Mersorb,from NUCON International, Inc., or AxTrap 277 from Axens—IFP GroupTechnologies, or the like, may be used.

Sequence Step K, Ammonia Removal [K]

FIG. 21 depicts Sequence Step K, Ammonia Removal [K], wherein AmmoniaRemoval Control Volume [K-1] accepts an ammonia laden Sequence Step KSyngas Inlet [K-IN], and outputs an ammonia-depleted Sequence Step KSyngas Discharge [K-OUT].

The Ammonia Scrubber [8800], configured similar to the Chlorine Scrubber[8500], is also a vertically oriented cylindrical, or rectangular,pressure vessel having a lower section, and an upper section, along witha central section that contains a specified quantity of packedabsorption media, which is supported upon a suitable support grid systemcommonplace to industrial chemical equipment systems. The upper sectionof the scrubber preferably contains a demister that is positioned abovea scrubber spray nozzle system [736] which introduces the scrubbingabsorption liquid to the scrubber.

The purpose of the Ammonia Scrubber is to remove trace amounts ofnitrogenated compounds including ammonia and hydrogen cyanide from thesyngas by using water as the main scrubbing absorption liquid.

Syngas enters the lower section of the Ammonia Scrubber and passes upthrough the scrubber's central section where the syngas vapor comes intointimate contact with the water scrubbing liquid travelingcountercurrently via gravity flow down through the scrubber's packing. Alevel control loop, comprising a level transmitter [700], positioned onthe lower section of the scrubber, and a level control valve [702], maybe automatically operated to permit water to be bled from the scrubberwater recirculation piping [738], via a waste water transfer conduit[740], to maintain a steady liquid level within the lower section of thescrubber. A scrubber water recirculation pump [776], accepts water fromthe lower section of the scrubber, through the pump suction piping[742], and transfers the water through the scrubber's spray nozzlesystem [736] and into the upper section of the scrubber where the flowof liquid is directed downwards onto the scrubber central packing.Process water [714] may be transferred to the scrubber waterrecirculation piping, or the lower section of the scrubber.

Sequence Step L, Ammonia Polishing [L]

FIG. 22 depicts Sequence Step L, Ammonia Polishing [L], wherein AmmoniaPolishing Control Volume [L-1] accepts a Sequence Step L Syngas Inlet[L-IN], and outputs a Sequence Step L Syngas Discharge [L-OUT].

The Ammonia Guard Bed [8825] is comprised of preferably a verticalcylindrical pressure vessel containing molecular sieve type 4A whichpossess an affinity to sorb trace amounts of nitrogenated compoundsincluding ammonia and hydrogen cyanide. Alternatively, sorbents such 5A,13X, dealuminated faujasite, dealuminated pentasil, and clinoptilolite,or the like, may be used.

Sequence Step M, Heat Addition [M]

FIG. 23 depicts Sequence Step M, Heat Addition [M], wherein HeatAddition Control Volume [M-1] accepts a Sequence Step M Syngas Inlet[M-IN], and outputs a Sequence Step M Syngas Discharge [M-OUT].

The Heat Exchanger [8850] is preferably of a shell- and tube type, wheresyngas is routed to the tube-side. Steam located on the shell-side ofthe exchanger elevates the temperature of the syngas from between 75 to125 degrees F. to between 350 and 450 degrees Fahrenheit.

The Heat Exchanger [8850] is equipped with a heat source [780] and aheat discharge [782] that communicate with the shell-side to indirectlytransfer heat to the syngas. Alternately, the heater may be electricallydriven, or flue gas or another alternate heat source may be utilized inthe place of steam to increase the temperature of the syngas.

Sequence Step N, Carbonyl Sulfide Removal [N]

FIG. 24 depicts Sequence Step N, Carbonyl Sulfide Removal [N], whereinCarbonyl Sulfide Removal Control Volume [N-1] accepts a carbonyl sulfideladen Sequence Step N Syngas Inlet [N-IN], and outputs a sulfur-depletedSequence Step N Syngas Discharge [N-OUT].

The Carbonyl Sulfide Hydrolysis Bed [8875] is comprised of preferably avertical cylindrical pressure vessel containing a packed bed media,comprised of alumina or titania, either in the form of beads, pellets,granules, spheres, packing, or the like and serves the purpose tohydrolyze carbonyl sulfide into hydrogen sulfide and carbon dioxideprior to the hydrogen sulfide polishing step. Water [790] in the form ofsteam may be injected into the hydrolysis bed aide the carbonyl sulfideto react with water to hydrolyze into hydrogen sulfide and carbondioxide over the packed bed media. It is preferred to accomplish thegoals of this sequence step with the utilization of a packed bed of analumina based material which allows for the hydrolysis of carbonylsulfide into carbon dioxide and hydrogen sulfide, however any type ofcarbonyl sulfide removal system or method, such as adsorption orabsorption type systems, may be employed to accomplish the goal of thesequence step to remove carbonyl sulfide from syngas.

Sequence Step O, Sulfur Polishing [O]

FIG. 25 depicts Sequence Step O, Sulfur Polishing [O], wherein SulfurPolishing Control Volume [O-1] accepts Sequence Step O Syngas Inlet[O-IN], and outputs Sequence Step O Syngas Discharge [O-OUT].

The Sulfur Guard Bed [8900] is comprised of preferably a verticalcylindrical pressure vessel containing a sorbent media, comprised ofzinc oxide in the form of beads, pellets, granules, spheres, packing, orthe like and serves the purpose to adsorb trace amounts of hydrogensulfide and elemental sulfur.

Sequence Step P, Carbon Dioxide Removal [P]

FIG. 26 depicts Sequence Step P, Carbon Dioxide Removal [P], whereinCarbon Dioxide Removal Control Volume [P-1] accepts a carbon dioxideladen Sequence Step P Syngas Inlet [P-IN], and outputs a carbon dioxidedepleted Sequence Step P Syngas Discharge [P-OUT]. The Heat Exchange CO2Separator serves the purpose to remove the carbon dioxide from thepressurized syngas and recycle it for utilization somewhere else. It ispreferred to recycle the separated carbon dioxide as an oxidant withinthe Hydrocarbon Reformer [8000], or for use in the upstream syngasgeneration process as a fluidization medium, or as vapor purges oninstrumentation and sampling ports and connections.

The equipment functionality as described above in Sequence Step I,Option 1, of FIG. 18 is identical to that of the preferred embodimentsituated within Dioxide Removal Control Volume [Q-1] of Sequence Step P,Carbon Dioxide Removal [P]. However, one main difference exists in thatthe Heat Exchange CO2 Separator [8925A&B] is preferentially comprised ofa shell and tube heat exchanger, preferably equipped with ½″ diametertubes. It is preferred to dispose an activated carbon fiber material,preferably in the form of spiral wound activated carbon fiber fabric, orbraided activated carbon fiber cloth strands, within the tube sideparticulate bed [810] of the vessel while the shell-side thermaltransfer chamber [804] runs empty except when undergoing a regenerationcycle.

The regeneration process as described above in Sequence Step I, Option1, of FIG. 18 is identical to that of the preferred embodiment situatedwithin Dioxide Removal Control Volume [P-1] of Sequence Step P, CarbonDioxide Removal [P], except for the fact that the Sequence Step P doesnot utilize a vacuum system. Instead, the regenerate product line [830]is in communication with a Carbon Dioxide Accumulator [8950]. Thepurpose of the Carbon Dioxide Accumulator [8950] is to providesufficient volume and residence time for regenerated carbon dioxideladen syngas vapors, transferred from a regeneration cycle, to be storedfor utilization somewhere else by transferring the carbon dioxidethrough a Sequence Step P Carbon Dioxide Discharge [CO2-OUT]. Theaccumulator operates at a pressure of 100 to 165 psia.

Alternatively, a membrane or sorption based carbon dioxide recovery unitmay be used to accomplish the goals of carbon dioxide removal andrecovery defined by Sequence Step P, Carbon Dioxide Removal [P]. In afurther embodiment, carbon dioxide may be reduced within this sequencestep by use of a carbon dioxide electrolyzer.

Sequence Step Q, R, S: Heat Addition [Q]; Steam Methane Reforming [R];Heat Removal [S]

With reference to FIG. 27, Sequence Step Q, Heat Addition [Q], SequenceStep R, Steam Methane Reforming [R], and Sequence Step S, Heat Removal[S] are combined in a preferred fashion as to realize an energyintegrated system capable of reforming hydrocarbons present in the inletsyngas source [P-IN]. This configuration is preferred when utilizing theoptional gaseous hydrocarbon source [HC-IN] routed to the inlet of theSyngas Compressor [8600].

A Heat Exchanger [8975] accepts a gaseous hydrocarbon laden syngasSequence Step Q Syngas Inlet [Q-IN] and elevates its temperature to theoperating temperature of the Steam Methane Reformer [9000]. This isaccomplished by utilization of heat transfer integration with thereformed cleaned and conditioned syngas [R-OUT] transferred a the sharedheat transfer surface within the Heat Exchanger [8975]. An oxidantsource [850] is made available to the Steam Methane Reformer [9000] toensure complete decomposition of the gaseous hydrocarbons into carbonmonoxide and hydrogen. A cooled syngas depleted of undesirable gaseoushydrocarbons [S-OUT] is discharged from the Heat Exchanger [8975] to bemade available to a downstream syngas processing technology.

Syngas Processing Embodiments

Those of ordinary skill in the art will recognize that fewer that all ofthe steps B-S of FIG. 1 may be used in a given syngas processing methodand system.

For instance, in a first syngas processing method, only steps C, D, G,H, K, O and T may be practiced, and the corresponding system willinclude the equipment required to implement these steps.

In a second syngas processing method, only steps B, C, D, F, G, H, I, K,M, N, O and T may be practiced, and the corresponding system willinclude the equipment required to implement these steps.

FIGS. 30A-30F present a number of syngas processing embodiments that onemight wish to implement. Each row of the table in FIGS. 30A-30F presentsthe steps to be practiced in a single syngas processing embodiment. Itis understood that the corresponding elements necessary to realize eachsuch method would be needed in a system for that embodiment. method.

EQUIPMENT LIST

The following list of equipment presents items that should beunderstandable to those of ordinary skill in the art familiar of syngasprocessing.

8000 Hydrocarbon Reformer 8025 Heat Recovery Steam Generator (HRSG)Superheater 8050 Heat Recovery Steam Generator (HRSG) 8075 Steam Drum8100 Venturi Scrubber 8125 Char Scrubber 8150 Char Scrubber HeatExchanger 8175 Continuous Candle Filter Decanter 8200 Filtrate BackflushBuffer Tank 8225 Filter Cake Liquid Removal System 8250 Liquid DepletedSolids Collection 8275 Decanter 8300 Continuous Candle Filter 8325 SVOCFlash Tank Heat Exchanger 8350 SVOC Flash Tank 8375 Solvent Cooler 8400SVOC Condenser 8425 SVOC Vacuum System 8450 Guard Filter 8475 SVOCSorptive Separator 8500 Chlorine Scrubber 8525 Chlorine Scrubber HeatExchanger 8550 Sulfur Scrubber 8575 Particulate Filter 8600 SyngasCompressor 8625 Aromatic Hydrocarbon Micro-Scale Heat Exchange Adsorber8650 VOC Condenser 8675 VOC Vacuum System 8700 Aromatic HydrocarbonFluidized Sorption Bed 8725 Regen Heat Exchange Fluidized Bed 8750Sorbent Transfer Tank 8775 Metals Guard Bed 8800 Ammonia Scrubber 8825Ammonia Guard Bed 8850 Heat Exchanger 8875 Carbonyl Sulfide HydrolysisBed 8900 Sulfur Guard Bed 8925 Heat Exchange CO2 Separator 8950 CarbonDioxide Accumulator 8975 Heat Exchanger 9000 Steam Methane Reformer

LIST OF REFERENCE NUMERALS

-   Sequence Step B Syngas Inlet [B-IN]-   Sequence Step B Syngas Discharge [B-OUT]-   Sequence Step C Syngas Inlet [C-IN]-   Sequence Step C Syngas Discharge [C-OUT]-   Sequence Step D Syngas Inlet [D-IN]-   Sequence Step D Syngas Discharge [D-OUT]-   SVOC Separation System Control Volume SVOC Discharge [SVOC-OUT]-   Sequence Step E Syngas Inlet [E-IN]-   Sequence Step E Syngas Discharge [E-OUT]-   Sequence Step F Syngas Inlet [F-IN]-   Sequence Step F Syngas Discharge [F-OUT]-   Sequence Step G Syngas Inlet [G-IN]-   Sequence Step G Syngas Discharge [G-OUT]-   optional gaseous hydrocarbon source [HC-IN]-   Sequence Step H Syngas Inlet [H-IN]-   Sequence Step H Syngas Discharge [H-OUT]-   Sequence Step I Syngas Inlet [I-IN]-   VOC Separation System Control Volume VOC Discharge [VOC-OUT]-   Sequence Step I Syngas Discharge [I-OUT]-   Sequence Step J Syngas Inlet [J-IN]-   Sequence Step J Syngas Discharge [J-OUT]-   Sequence Step K Syngas Inlet [K-IN]-   Sequence Step K Syngas Discharge [K-OUT]-   Sequence Step L Syngas Inlet [L-IN]-   Sequence Step L Syngas Discharge [L-OUT]-   Sequence Step M Syngas Inlet [M-IN]-   Sequence Step M Syngas Discharge [M-OUT]-   Sequence Step N Syngas Inlet [N-IN]-   Sequence Step N Syngas Discharge [N-OUT]-   Sequence Step O Syngas Inlet [O-IN]-   Sequence Step O Syngas Discharge [O-OUT]-   Sequence Step P Syngas Inlet [P-IN]-   Sequence Step P Syngas Discharge [P-OUT]-   Sequence Step P Carbon Dioxide Discharge [CO2-OUT]-   Sequence Step Q Syngas Inlet [Q-IN]-   Sequence Step Q Syngas Discharge [Q-OUT]-   Sequence Step R Syngas Inlet [R-IN]-   Sequence Step R Syngas Discharge [R-OUT]-   Sequence Step S Syngas Inlet [S-IN]-   Sequence Step S Syngas Discharge [S-OUT]-   Hydrocarbon Reforming Control Volume [B-1]-   Syngas Cooling Control Volume [C-1]-   Solids Removal & SVOC Removal Control Volume [D-1]-   Chlorine Removal Control Volume [E-1]-   Sulfur Removal Control Volume [F-1]-   Particulate Filtration Control Volume [G-1]-   VOC Removal Control Volume [I-1]-   Metal Removal Control Volume [J-1]-   Ammonia Removal Control Volume [K-1]-   Ammonia Polishing Control Volume [L-1]-   Heat Addition Control Volume [M-1]-   Carbonyl Sulfide Removal Control Volume [N-1]-   Sulfur Polishing Control Volume [O-1]-   Carbon Dioxide Removal Control Volume [P-1]-   SVOC Separation System Control Volume [SVOC-1]-   additives [2]-   oxidant source[4]-   gaseous hydrocarbon source [6]-   superheated steam [8]-   HRSG transfer line [10]-   water [12]-   steam and water mixture [14]-   pressure transmitter [16]-   pressure control valve [18]-   saturated steam transfer line [20]-   level transmitter [22]-   level control valve [24]-   water supply line [26]-   steam drum continuous blowdown line [28]-   Venturi Scrubber recirculation water line [30]-   Venturi Scrubber recirculation solvent line [32]-   Venturi Scrubber to Char Scrubber transfer conduit [34]-   scrubber spray nozzle system [36]-   Char Scrubber recirculation water [38]-   Char Scrubber recirculation solvent [40]-   Char Scrubber underflow downcomer [42]-   common water recirculation line [44]-   cooling water supply [46]-   cooling water return [48]-   upright tank [50]-   central section [52]-   closed dome shaped top [54]-   conical lower sections [56 a & 56 b]-   drain valve [58 a & 58 b]-   drain line [60 a & 60 b]-   vertical underflow weir [62]-   upright vertical housing wall [64]-   annular passageway [66]-   common water header [68]-   water take-off nozzles [70 a & 70 b]-   water recirculation pump [72]-   inner solvent chamber [74]-   solvent and water interface rag-layer [78]-   filter bundles [80 a & 80 b]-   candle filter elements [82]-   filter bundle common register [84 a & 84 b]-   filtrate removal conduit [86 a & 86 b]-   filtrate process pump [88]-   common filtrate suction header [90]-   filtrate register valve [92 a & 92 b]-   filtrate solvent transfer line [94]-   alternate backflush transfer line [95]-   common solvent recirculation line [96]-   pressure transmitters [98 a & 98 b]-   housing pressure transmitter [100]-   flow indicating sight glasses [102 a & 102 b]-   SVOC-depleted solvent transfer line [104]-   level transmitter [106]-   solvent supply level control valve [108]-   solvent supply line [110]-   solvent backflush pump [112]-   filtrate transfer conduit [114]-   backflush tank recirculation line [116]-   restriction orifice [118]-   backflush filtrate regen valves [120 a & 120 b]-   filtrate backflush regen conduit [122 a & 122 b]-   liquid removed from the filter cake [124]-   waste water header [126]-   solids & SVOC laden solvent filtrate transfer line [128]-   SVOC laden solvent filtrate transfer line [130]-   alternate backflush transfer line [131]-   steam inlet line [132]-   steam discharge line [134]-   SVOC laden filtrate solvent Flash Tank transfer line [136]-   pressure letdown device [138]-   SVOC flash transfer conduit [140]-   SVOC-depleted solvent transfer line [142]-   SVOC-depleted solvent transfer pump [144]-   solvent transfer line [146]-   solvent recycle line [148]-   cooling water supply [150]-   cooling water return [152]-   impingement baffle [154]-   spray nozzles [156]-   CIP agent transfer line [158]-   CIP agent isolation valve [160]-   cooled SVOC-depleted solvent transfer line [162]-   SVOC vacuum system transfer line [164]-   liquid SVOC seal fluid [166]-   vacuum system vent line [168]-   cooling water supply [170]-   cooling water return [172]-   porous membrane [174]-   porous chemical resistant coating [176]-   SVOC laden solvent membrane process surface [178 a]-   SVOC permeate membrane process surface [178 b]-   filtrate solvent transfer line [180]-   level transmitter [200]-   level control valve [202]-   process water [214]-   scrubber spray nozzle system [236]-   scrubber water recirculation piping [238]-   water transfer conduit [240]-   pump suction piping [242]-   cooling water supply [246]-   cooling water return [248]-   recirculation pump [276]-   level transmitter [300]-   level control valve [302]-   process water [314]-   sulfur scavenger derived solution [316]-   scrubber spray nozzle system [336]-   scrubber water recirculation piping [338]-   water transfer conduit [340]-   pump suction piping [342]-   recirculation pump [376]-   adsorption chamber [402]-   thermal transfer chamber [404]-   feed inlet [406 a & 406 b]-   product outlet [408 a & 408 b]-   particulate bed [410]-   thermal transfer chamber inlet valve [412 a & 412 b]-   inlet valve [414 a & 414 b]-   product outlet valve [416 a & 416 b]-   purge inlet valve [418 a & 418 b]-   depressurization valve [420 a & 420 b]-   modulating purge valve [422]-   regenerate product line [430]-   VOC vacuum system transfer line [464]-   liquid VOC seal fluid [466]-   vacuum system vent line [468]-   cooling water supply [470]-   cooling water return [472]-   distribution plate [474]-   support grid system [476]-   adsorbent bed material [478]-   vapor bubbles [480]-   internal cyclone [482]-   freeboard section [484]-   cyclone dipleg [486]-   VOC adsorbent transfer conduit [488]-   solids handling valves [490 a & 490 b]-   VOC-depleted vapor source [492]-   distribution plate [494]-   support grid system [496]-   heat source [498]-   heat transfer chamber [500]-   heat transfer surface [502]-   vapor bubbles [504]-   gaseous hydrocarbon vapor [506]-   internal cyclone [508]-   freeboard section [512]-   cyclone dipleg [514]-   solids handling valves [516 a & 516 b]-   transfer conduit [518]-   dip tube [520]-   vapor source [522]-   solids handling valves [524 a & 524 b]-   regen adsorbent transport line [526]-   perforated trays [528]-   level transmitter [700]-   level control valve [702]-   process water [714]-   scrubber spray nozzle system [736]-   scrubber water recirculation piping [738]-   water transfer conduit [740]-   pump suction piping [742]-   recirculation pump [776]-   heat source [780]-   heat discharge [782]-   water [790]-   adsorption chamber [802]-   thermal transfer chamber [804]-   feed inlet [806 a & 806 b]-   product outlet [808 a & 808 b]-   particulate bed [810]-   thermal transfer chamber inlet valve [812 a & 812 b]-   inlet valve [814 a & 814 b]-   product outlet valve [816 a & 816 b]-   purge inlet valve [818 a & 818 b]-   depressurization valve [820 a & 820 b]-   modulating purge valve [822]-   regenerate product line [830]-   oxidant source [850]

SEQUENCE STEP LIST

-   Syngas Generation [A]-   Sequence Step B, Hydrocarbon Reforming [B]-   Sequence Step C, Syngas Cooling [C]-   Sequence Step D, Solids Removal & SVOC Removal [D]-   Sequence Step E, Chlorine Removal [E]-   Sequence Step F, Sulfur Removal [F]-   Sequence Step G, Particulate Filtration [G]-   Sequence Step H, Syngas Compression [H]-   Sequence Step I, VOC Removal [I]-   Sequence Step J, Metal Removal [J]-   Sequence Step K, Ammonia Removal [K]-   Sequence Step L, Ammonia Polishing [L]-   Sequence Step M, Heat Addition [M]-   Sequence Step N, Carbonyl Sulfide Removal [N]-   Sequence Step O, Sulfur Polishing [O]-   Sequence Step P, Carbon Dioxide Removal [P]-   Sequence Step Q, Heat Addition [Q]-   Sequence Step R, Steam Methane Reforming [R]-   Sequence Step S, Heat Removal [S]-   Clean Syngas For End User [T]-   Sequence Step B Syngas Inlet [B-IN]-   Sequence Step B Syngas Discharge [B-OUT]-   Sequence Step C Syngas Inlet [C-IN]-   Sequence Step C Syngas Discharge [C-OUT]-   Sequence Step D Syngas Inlet [D-IN]-   Sequence Step D Syngas Discharge [D-OUT]-   SVOC Separation System Control Volume SVOC Discharge [SVOC-OUT]-   Sequence Step E Syngas Inlet [E-IN]-   Sequence Step E Syngas Discharge [E-OUT]-   Sequence Step F Syngas Inlet [F-IN]-   Sequence Step F Syngas Discharge [F-OUT]-   Sequence Step G Syngas Inlet [G-IN]-   Sequence Step G Syngas Discharge [G-OUT]-   optional gaesous hydrocarbon source [HC-IN]-   Sequence Step H Syngas Inlet [H-IN]-   Sequence Step H Syngas Discharge [H-OUT]-   Sequence Step I Syngas Inlet [I-IN]-   VOC Separation System Control Volume VOC Discharge [VOC-OUT]-   Sequence Step I Syngas Discharge [I-OUT]-   Sequence Step J Syngas Inlet [J-IN]-   Sequence Step J Syngas Discharge [J-OUT]-   Sequence Step K Syngas Inlet [K-IN]-   Sequence Step K Syngas Discharge [K-OUT]-   Sequence Step L Syngas Inlet [L-IN]-   Sequence Step L Syngas Discharge [L-OUT]-   Sequence Step M Syngas Inlet [M-IN]-   Sequence Step M Syngas Discharge [M-OUT]-   Sequence Step N Syngas Inlet [N-IN]-   Sequence Step N Syngas Discharge [N-OUT]-   Sequence Step O Syngas Inlet [O-IN]-   Sequence Step O Syngas Discharge [O-OUT]-   Sequence Step P Syngas Inlet [P-IN]-   Sequence Step P Syngas Discharge [P-OUT]-   Sequence Step P Carbon Dioxide Discharge [CO2-OUT]-   Sequence Step Q Syngas Inlet [Q-IN]-   Sequence Step Q Syngas Discharge [Q-OUT]-   Sequence Step R Syngas Inlet [R-IN]-   Sequence Step R Syngas Discharge [R-OUT]-   Sequence Step S Syngas Inlet [S-IN]-   Sequence Step S Syngas Discharge [S-OUT]-   Hydrocarbon Reforming Control Volume [B-1]-   Syngas Cooling Control Volume [C-1]-   Solids Removal & SVOC Removal Control Volume [D-1]-   Chlorine Removal Control Volume [E-1]-   Sulfur Removal Control Volume [F-1]-   Particulate Filtration Control Volume [G-1]-   VOC Removal Control Volume [I-1]-   Metal Removal Control Volume [J-1]-   Ammonia Removal Control Volume [K-1]-   Ammonia Polishing Control Volume [L-1]-   Heat Addition Control Volume [M-1]-   Carbonyl Sulfide Removal Control Volume [N-1]-   Sulfur Polishing Control Volume [O-1]-   Carbon Dioxide Removal Control Volume [P-1]-   SVOC Separation System Control Volume [SVOC-1]-   filtration [step 950]-   filter bundle isolation [step 952]-   filtrate backflush [step 954]-   filter cake sedimentation [step 956]-   filter cake discharge start [step 958]-   filter cake discharge end [step 960]-   filtration restart preparation [step 962]-   Step D1 a-   Step D1 b-   Step D1 c-   Step D1 ca-   Step D1 cb-   Step D1 d-   Step D1 e

What is claimed is:
 1. A method for removing solids and semi-volatileorganic compounds (SVOC) from unconditioned syngas having steamcontained therein, the unconditioned syngas having a first temperatureabove a SVOC condensation temperature, the method comprising: (a)contacting the unconditioned syngas with a solvent and water to reducethe temperature of the syngas to below the SVOC condensation temperatureto thereby form an intermediate SVOC-depleted syngas containing steam,and a first mixture comprising SVOC, solids, solvent and water; (b)removing steam from the intermediate SVOC-depleted syngas containingsteam to form: (i) a first depleted syngas stream which has a reducedamount of SVOC relative to the unconditioned gas stream, and (ii) asecond mixture comprising SVOC, solids, solvent and water; (c)separating the water within the second mixture based upon immiscibilityso that the SVOC, solids and solvent collect together to form a thirdmixture above the water; (d) separating the solids from the SVOC andsolvent in a vessel having at least one liquid phase candle filter suchthat the solids agglomerate on a surface of the candle filter and form afilter cake having density greater than that of water within the vessel;(e) backflushing the candle filter to loosen the filter cake so that thefilter cake sinks into the water within the vessel; and (f) removing thefilter cake from a bottom of the vessel.
 2. The method according toclaim 1, comprising using a Fischer-Tropsch liquid product as thesolvent.
 3. The method according to claim 2, comprising using amid-distillate or Medium Fraction Fischer-Tropsch Liquid (MFTL) as thesolvent.
 4. The method according to claim 1, comprising: removing theSVOC and solvent from the vessel through the candle filter; andbackflushing the candle filter using a recirculated portion of theremoved SVOC and solvent.
 5. The method according to claim 4, comprisingseparating the SVOC from the solvent and recycling the solvent, afterthe SVOC and solvent have been removed from the vessel.
 6. The methodaccording to claim 4, comprising separating the SVOC from the solventusing vacuum flashing, after the SVOC and solvent have been removed fromthe vessel.
 7. The method according to claim 4, comprising separatingthe SVOC from the solvent using membranes, after the SVOC and solventhave been removed from the vessel.
 8. The method according to claim 1wherein the unconditioned syngas comprises: carbon monoxide from about 5to 35 vol % dry, hydrogen from about 20 to 60 vol % dry, methane fromabout 1 to 15 vol % dry, SVOC from about 10 to 1,000 ppmV dry, solidsfrom about 0 to 1 wt %, and VOC from about 500 to 10,000 ppmV dry. 9.The method according to claim 8 wherein the first depleted syngas streamhas 80 to 99% less solids and has 95 to 99% less SVOC relative to theunconditioned gas stream.
 10. The method according to claim 1,comprising: separating the water within the second mixture based uponimmiscibility in a decanter; transferring the third mixture from thedecanter to the vessel having the candle filter therein.
 11. The methodaccording to claim 1, wherein the solvent is a biodegradable solventsuitable for biodiesel residue.
 12. The method according to claim 1wherein the first depleted syngas stream has 80 to 99% less solids andhas 95 to 99% less SVOC relative to the unconditioned gas stream.
 13. Amethod for removing solids and semi-volatile organic compounds (SVOC)from unconditioned syngas having steam contained therein, theunconditioned syngas having a first temperature above a SVOCcondensation temperature, the method comprising: (a) contacting theunconditioned syngas with water to reduce the temperature of the syngasto below the SVOC condensation temperature to thereby form anintermediate SVOC-depleted syngas containing steam, and a first mixturecomprising SVOC, solids and water; (b) removing steam from theintermediate SVOC-depleted syngas containing steam to form: (i) a firstdepleted syngas stream which has a reduced amount of SVOC and solidsrelative to the unconditioned gas stream, and (ii) a second mixturecomprising SVOC, solids and water; (c) separating the water within thesecond mixture based upon immiscibility so that the SVOC and solidscollect together to form a third mixture separate from the water; (d)agglomerating the solids together to form a agglomerated cake havingdensity greater than that of water; and (e) applying mechanical pressureto the agglomerated cake to remove residual liquid therefrom to form aliquid depleted solids.
 14. The method according to claim 13 wherein theunconditioned syngas comprises: carbon monoxide from about 5 to 35 vol %dry, hydrogen from about 20 to 60 vol % dry, methane from about 1 to 15vol % dry, SVOC from about 10 to 1,000 ppmV dry, solids from about 0 to1 wt %, and VOC from about 500 to 10,000 ppmV dry.
 15. The methodaccording to claim 14 wherein the first depleted syngas stream has 80 to99% less solids and has 95 to 99% less SVOC relative to theunconditioned gas stream.
 16. The method according to claim 13, wherein:in step (a), the unconditioned syngas is contacted with water and asolvent; and the solvent is a Fischer-Tropsch liquid product.
 17. Themethod according to claim 16, comprising using a mid-distillate orMedium Fraction Fischer-Tropsch Liquid (MFTL) as the solvent.
 18. Themethod according to claim 13 wherein the first depleted syngas streamhas 80 to 99% less solids and has 95 to 99% less SVOC relative to theunconditioned gas stream.
 19. The method according to claim 13,comprising: separating the water within the second mixture based uponimmiscibility in a decanter; transferring the third mixture from thedecanter to the vessel having the candle filter therein.
 20. The methodaccording to claim 13, wherein: in step (a), the unconditioned syngas iscontacted with water and a solvent; and the solvent is a biodegradablesolvent suitable for biodiesel residue.